Just have time for a brief comment. Sorry Ex is pregnant. But it's her life not yours.
What bothers me (besides what Gineen has pointed out about ex & your obsession/comparisons) is YouR obsession with body types and the beauty/ cheerleader thing. Come on man - how shallow can you be? Look what that type brought you.
I've been with a "nerd" type for almost 10 years now. I love my nerd. He is never who I thought I wanted but there is no drama. He is good to me. He is intelligent & can carry a good conversation. I will never tire of that. He is self sufficient, loves to do nice things for me & makes damn good $. If you let that woman go - you are nuts!
Go back to your C & work on this. Redirect your thoughts about ex. Just think "good for her". Smile that YOU don't have a baby on the way. And keep on being a great dad!