[Shirazmn]

Thanks, Shirazmn and DiDi!
Yeah, the fit is not ideal, I probably really should get my own bra and try out a DD cup.
My wife's bras more or less work on me, but there really is a lot of squishing and a bit of a quadboob going on (great descriptive term by the way )
The only issue is hiding the bras...there's a lot I'd like to try but I can't, like getting some feminine clothes and bras, shaving my chest, pumping, and so on.
It'd be a lot easier if I managed to get my wife on board with this experiment but well, I'm not brave enough for that...yet.

Weird thing about sizing is that it seems to vary so much between bra models, getting a proper bra seems more like art than science.
I was curious and tried out another one, this one is 38C and weirdly enough seems to contain me a bit better and is more comfortable than the D-cup one. Huh. I'll get my measurements and see what that calculator tells me.

[kanony]

Shirazmn, did you mean to write something? I only see my quoted post

I took my measurements today, using the calculator Lara mentioned. 
I took 3 measurements and averaged them. The measurements came out mostly similar with 1-2 cm variance, but it does seem to depend a lot on the exact place the band would be on your back. I tried to keep it level, not much below the breast line and not too high either. I used the "Assigned male at birth" measurement option.

Loose Underbust: 113
Snug Underbust: 110
Tight Underbust: 105
Standing Bust: 124
Leaning Bust: 127
Lying Bust: 122

It comes down to 42DD/E(UK), 42 DD/DDD (US) and 95F/G (EU).
It seems to suggest at least one cup size bigger than I would've thought myself but I'm not complaining
The larger band size is also reasonable, my wife's 38 band size bras would definitely be too tight to wear all day.

In other news, I think PM and progesterone cream are starting to work. There's been a dull throbbing ache behind my nipples and deep in my breasts all morning today.

[HelloDiDi]

Just as expected, your boobs are way bigger than the bras in the pictures. Your result seems to be in line with how you look like in the pics. I suggest you to try out going one bigger on cups and one smaller on band, depending on the brand, either 40 or 42 band is likely the best fit. You DO WANT to have a snug fitting band because that is where most of the support comes from, and ditch two hooked slim bands and go for three or four because you DO WANT good support and wider bands tend to feel more comfy. 

There's usually wiggle room one size on both band and cup depending on which bra it is, so keep that in mind. Typically ABTF calculator is very accurate so give or take one size, that's what will likely fit you. "Assigned male at birth" setting typically drops cup size by one as it compensates for likelyhood of wider chest, that's the only thing it does, you can check your result on all settings to see what the difference is.

[Shirazmn]

Shirazmn, did you mean to write something? I only see my quoted post

Nooooooooooooo!!! My uselessly long comment written with a lot of pain from my phone has gone lost.

OK, it was more or less like this:

I don't know your family life and I don't mean to intrude, but hasn't your wife noticed that you have nice, round, big, feminine breasts? I am asking you because you say that she may not be on board with buying bras, but she must see that you could suffer from all the feminine problems created by a pair of breasts like the ones you have. Bras shouldn't be a taboo. I mean, maybe hot pink frilly push-up bras might be a bit much at the beginning, but sports bras and t-shirt bras (for when you are at home) should be a fair request. Women should know that carrying boobs like yours without a bra could cause back pain, stretch marks, etc... have you tried introducing the idea that you might need a bra as much as anyone with breasts does?

[kanony]

Fair question  
I'm used to maintaining an outwardly masculine persona, I've done this ever since my boobs first started growing when I was a teenager. So this is also what I acted like when we first met. 
Looking back, she did try to "test" me several times at start, she used to wonder how I'd look in her lingerie or how I'd look with makeup or lipstick on. Being a tough guy like I am, I just laughed it off. 
But in reality even these pretty mild comments used to send me into deep shame, crossdressing and gender dysphoria spirals. Growing up with boobs as a dude tends to give you a hair trigger about this I guess.
She probably picked up on some vibes related to it, stopped paying attention to them and my breasts basically became a taboo topic in our relationship for a while. She only commented on them or touched them when she was pissed off at me, because she knew I'd get weird about it.

A few years ago, things started somehow thawing again though. When talking about each other's favourite attributes, she said that she thinks my best assets are my breasts and butt. Sadly, when I suggested that it should be my dick instead, she just laughed and shook her head.
She also now sometimes asks me to wear tight tshirts, because they "bring out my curves". She also very occasionally grabs my breasts when we have sex. It has always made me finish pretty much instantly, which is super embarassing.

But some essential barrier about this is still unbroken. I guess neither of us are willing to break a familiar and working pattern because we're still not sure how the other person would react and where it would lead. I don't even know myself, outside I am a straight man but on the inside I'm a bisexual sissy who enjoys having big bouncing tits on her chest. Should I let her out or not?

The masculine role is useful, familiar and its what she likes in bed, and in a man. The occasional flashes of femininity are allowed, but wearing a bra? It's a huge step up and a pretty clear signal towards embracing femininity.
I'm sure we both have our theories and know more than we let show, but how much? Is it tolerated as long as it's covert? Does she actually want it to be more overt? How many layers of Yomi are there between us?  
Maybe I'll find out eventually.

[Shirazmn]

I do relate a LOT with what you write, apart from the fact that I don't have boobs as nice or as big as yours.
Lovemaking with my wife has shifted a lot towards her sucking on my "breasts" because that's essentially the only way to make me finish in less than 40 minutes. (I mean... both outcomes have their own perks...).

My wife knows that I crossdress but doesn't know that I have intentionally taken PM to gain some extra boobage. She does know that PM exist and that it can cause some breast growth but I always told her that the thing I am taking is to slow down my hair loss, which is not totally a lie. She was OK with my wearing panties 24/7 (boyshorts mostly, but some lace ones and things too) and she never really objected with bras as long as they wouldn't show through my clothing. Even now, the "deal" is that whatever I do MUST go unnoticed to my son, neighbor, and more or less all of her friends. I think that I am way more strict about these rules than she is, but I prefer to keep that "familiar and working pattern" that you are talking about.

Anyway, it's good to hear that she has a playful attitude towards your breasts. From what you say, she might really enjoy them. To be honest, they are so big that if she thought they were a problem, she wouldn't be with you in the first place. I think you should slowly reintroduce the subject, let her take the lead, and play along. Some bras can be very stealthy but they feel good and, in you case, they might actually help a lot.

[kanony]

Glad to hear that you've already managed to be open about your interests with her, (and keep the relationship too). I wouldn't want anything more either than wearing bras and panties and general crossdressing sometimes.
I'm hoping that once I manage to grow bigger and give my breasts a more feminine shape, she'll eventually bring up the subject of bras herself. The growth will probably happen slowly over time and it's not like I'm starting with a flat chest so I don't think it'll be suspicious. They'll just become impossible to ignore eventually

[Shirazmn]

They already are really hard to ignore right now ?

[kanony]

I don't think it's that bad yet...is it? Here's a few pics. I do try to hide or minimize them with clothing and posture, I'm used to doing it, like all dudes with gynecomastia I guess.
It does look really visible with a pulled tight tshirt like in first pic, but I just don't wear them like that IRL
Black or graphic oversized shirts that tent in front and make you look like a regular obese dude, keeping shoulders back to flatten the profile, dressing in layers...it all helps. And hoodies are a lifesaver, a critical piece of equipment that I nearly always wear in public
But if my breasts or nipples were to grow any bigger, I kinda would already need a minimizing bra to avoid stares, I think.

[Shirazmn]

Ok... objectively the jacked does a good job.
But a minimizing sport bra could do the same even under thinner clothes. Probably worth a shot.