Usually it's not selfless, usually it's an attempt to buy love as others have mentioned, even if the man isn't immediately aware. I mean is getting a tattoo of their initials after a few months of dating selfless? I don't think so. It could be, but the chances are slim imo. I'm willing to bet he's identifying heavily with their interactions and is going 'all in' without her reciprocity, which usually ends badly because of the immense time sink he's making it for himself.
@r4zorsharp has posted some extreme cringe in this thread. I had a feeling he was obsessed with his reaction score when reading how oversimplified his threads were. The comments he's made here have confirmed that to me. Lots of flexing and bashing other members for claiming to be such a 'cool guy'.