Here it goes. Me [39], GF [26], been together over 1.5 years. GF has always wanted bigger boobs. She's going 650 CC's possibly 700. ;)

I told her in advance, "Big, small, just yourself as you are, etc., I support you regardless, but no way am I putting money into them."

GF: "Why not?"

Me: "Man who pays is the last who plays. I know, I've played with a whole bunch of married fake tits."

She rolls her eyes

And I haven't put a dime into them. I've seen so many useful idiots part with cash to put in a car someone else is driving, myself included, hell no. I went to her first appointment with Doc. Surgery comes up next month.

I stand by my sentiment. I'll never buy boobs for a woman. She earned and saved the money herself. So I'll enjoy them as long as I can keep her interested.

Edit: As an aside, GF wants to go quite large on the boob scale. It's other women who have pushed back the hardest when she tells them what she wants.

Edit II: For the "fake boob" virtue signalers and concern trolls:

"Selfishness is not living as one wishes to live. It is asking others to live as one wishes to live. And unselfishness is letting other people's lives alone, not interfering with them. Selfishness always aims at creating around it an absolute uniformity of type. Unselfishness recognizes infinite variety of type as a delightful thing, accepts it, acquiesces in it, enjoys it. It is not selfish to think for oneself. A man who does not think for himself does not think at all. It is grossly selfish to require of one's neighbor that he should think in the same way, and hold the same opinions. Why should he? If he can think, he will probably think differently. If he cannot think, it is monstrous to require thought of any kind from him. A red rose is not selfish because it wants to be a red rose. It would be horribly selfish if it wanted all the other flowers in the garden to be both red and roses." - Oscar Wilde, The Soul of Man and Prison Writings

When you understand that quote, you are very free from a lot of social, cultural, and religious constructs.