Sounds like it could be postpartum depression. At least that should be ruled out first, if everything was great until you had your son.

This sounds like an extremely difficult situation and I’m really sorry that you’re dealing with this.

I don’t know if this relationship is salvageable, but I would recommend, for now, at least, that you stop flirting, and stop initiating physical contact with her that she clearly does not welcome. If she is depressed and there is something to save here, hugs and flirting that she has made clear she does not want may sour her on those forever by building negative associations. I’ve had partners who touched me when it was not welcome and even when I wanted to make the relationship work it was impossible to get past the self-protective impulse to pull away from touch that I had started to associate with someone violating my consent.