I guess I truly do love her and want to make her happy.
You can love someone, even be "in love" with them, and it can go both ways - and STILL NOT MAKE GOOD PARTNERS OR LIFETIME COMPANIONS.
"Love" is NOT all you need.
Who was taking care of your son while she was fucking around with everyone she knows? You? And this is the kind of "love" you want to use to set an example of what a loving relationship looks like?
I realize you're in a lot of pain and I'm not trying to kick you while you're down. I'm trying to get you to think about this rationally, like an outsider who has no investment in the outcome of the situation. YOU ARE IN CONTROL OF YOUR OWN ACTIONS. YOU HAVE CHOICES.