A lot of guys and girls need to real about the condition "Retroactive Jealously", it will help you identify why it bothers you, and what you need to do to learn to overcome it.
My life got ripped apart by a wife who lied repeatedly and now my kids have to live between two homes because she couldn't be honest. Be thankful all you lost was her, I lost my kids for 50% of my...
Just shut your mouth and make sure you graduate. Is it worth winning a petty arugument over someone who you dont give two craps about worth bringing all this stress on.
While a nice little rant, if the mom wants to have the kid its going to happen, and the OP has a responsiblity to ensure that child has the best life possible.