If we are going like that, there is no such thing as a selfless act anyway, we only do things for ourselves for how it will make us feel, humans are not selfless, and either way, are we playing the same game? the same game where when the Mc asked her not to fool around with Milly she listened even though she wanted? Also, the same shit can be said about the MC he doesn't want a relationship with his daughter because it would be best for her, he wants because it would be best for him, he went to protect her so he wouldn't feel guilty, he is trying to have a relationship with her because it feels good for him, the fact that is good for her is secondary.
Edit: also what does she getting layd has to do whith the father-daughter relationship? it has to do with the incest, sure, but not the father-daughter relationship.