Original post by fallen_acornsyou've hit a point where your now being asked to question what it means to be a man, and are you one? Its clear from your post, your gut is telling you to be a boy still, run away from the responsibility, run away rather then solving your relationship problems, and just escape from the situation.
But that's not what men do, not good men at least.
If you take the baby out of the equation, then yes you have a choice between
fixing your relationship (slow, hard work, maybe impossible)
or
leaving it (quick, easy, but will the next person be better)..
your still young enough that the second option is probably a good choice, just call it a day, and you still have a good few years to find someone else.
But then add the baby back in, and the balance changes. Now you have:
fixing your relationship (slow, hard work, maybe impossible, but you know your doing whats best for your son/daughter, and your doing your job as a dad by giving them the best shot at life)
or
leaving it (quick easy, but will the next person be better? especially as you tell all of your future partners that you already have a kid.. and that you left your pregnant girlfriend? I bet your future girlfriends are going to love dating a guy who left his pregnant girlfriend. And you feel guilty because you are mostly abandoning your child and giving up most of your responsibilities as a dad, something key to actually being a man.. and you have to deal with the fact that most of the people around you currently will not understand, and will think you a massive ******** for doing it. You will loose friends, and half of your childs family will hate you, and try and turn your child against you for ever. Your child may even blame you for what you did as it gets older)
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If I was in your shoes, I would try my best to make it work. It seems like you and your girlfriend are still dating like teenagers, bickering about who can be friends with who, fighting for control etc. You (both) need to grow up and act like a propper couple, so that your ready to take care of your baby. Being a man means taking responsibility for your actions, and the biggest responsibility you are ever given is that of your child, someone who depends on you and who needs you. Yes your passion has died down, thats normal, yes you argue and fight for control, thats normal.. both of those things are going to happen again with your next partner anyway... so why not try and make this one, the one where you have a kid involved, work.
Sit down with your partner, and be a man about it - tell her, dirrectly and honestly all the things you have been feeling, and don't cave and give in when she gets mad and upset with you (which she will) keep strong and weather the storm, and eventually she will come around. Get through this rough patch, and then work really hard to make sure that your life together is always special and always moving forward.. make compromises on your differences, and where she refuses to compromise, stand up to her so strongly that she knows there is no other option. Figure out how to live together and communicate as a propper couple, and how to keep the romance going after so many years (which takes constant work and effort, and cant be taken for granted). Look after your baby, and give it a good few years of hard work to see if you can make it all work.
If after a few years of constant work, you still can't make it work - then maybe your in a better place to look at other options. You wont face such a huge backlash for separating with a child, as you would separating when she is pregnant, and at least then you know that you gave it a really good amount of effort.. you truely tried your best to make things work for your kid, and your best isn't just a few months of trying.. its a few years of hard work to make things as good as they can be for your baby.