As mentioned by others ... don't know the whole story .... but, I don't know many women who wouldn't like a man to give them flowers, take them on dates, help with the housework and then not require anything in return .... I mean if we're looking for the fantasy! .... of course most of us live in the real world and must function there as well ... from what you've said, it doesn't sound like you are being selfish, in fact it sounds like she needs to take a look around at how hard many divorced moms have it and be grateful for a (soon to be) ex who is so interested in maintaining a peaceful and even flow between the 2 of you, especially so you son can have a peaceful and even flow in his life!

I'd say that if she's pushed you from the house and from being her partner ... then she doesn't get to require your support in any way other than in raising your son ... not that you can't help her out here and there to keep the peace, but don't let her tie up your free time which may well be better used in the pursuit of your own lasting happiness ... and that is not being selfish ... it's simply taking care of yourself. Best of luck!