Kelly,
I'm not really sure what you want your boyfriend to do. You're saying up there that you think he goes out too often with his friends, and then you are saying that you wouldn't care about him going out with his friends if you two went out together more often.
If he's truly spending too much time away from family, then you both need to set some parameters you are both willing to live with. Like he doesn't go out more than 2 nights a week, and you don't complain about it EVER, no matter what. That means he can go those two nights, with no pouting, no whining, no "can't you put it off just this one time" And that special events, like a friend's bachelor party, or something like that are flexible, unless they fall on YOUR birthday or Christmas.
If your real objection is that he's not going out with you, then you need to not use the other argument as a way to pick at him to get what you want. Have you asked him, outside of an argument, why he doesn't want the two of you to go out together? A lot of guys get funny about leaving the baby with a sitter (my husband. for example) and think it should be Mommy who stays home to tend the little one (not my husband, lucky for him!). So in that guy's mind, Mom wanting to go out for dinner or a movie or to a club, is being derelict in her duty.
Is the "forever" concept sinking in now that the baby's here? A lot of guys don't really "Get" the parenthood thing until it's literally staring them in the face. Then they freak out. So, he spends a little while running around, partying, and acting like a jerk until he settles into the idea that a family isn't really going to strangle him to death, and look how cute the little guy is, and maybe I'll stay home tonight, after all.
What you should do about him really comes down to what you expect from him personally, and what you expect from the relationship. In order for it to work, you both have to be 100% committed. How you work out the rules about going out and all is between you, but you both have to have a genuine desire to make the rules work, and you both have to go into negotiating those ground rules with a willing an open spirit. If not, it all falls down.