Because coming inside a girl changes her eggs' DNA and her future offspring will have some of your genes no matter who fathers it, how do you feel about coming inside a girl now?
> Spreading my DNA without fatherly obligations or having to pay child support.
Feels like revenge, almost. She's carrying a verifiable piece of my DNA with her for the rest of her life, and the dude that finally settles for her trashy whore ass has to raise a part of me. Fair trade for the emotional pain I went through.
On an objective level, most guys are going to have to deal with this problem, and only the worthless memers who cry about virgin gf's care about this even though they're never going to get a virgin gf.
tl;dr guys are civilised enough to be bros about rooting girls and accepting used goods as it's going to happen to 99% of us. Girls have to deal with being cum receptacles.