Hi L.,
Good for you that you are taking parenting classes. There are a lot of people who should and don't.
I personally think you should pay attention to the little voice inside you--your conscience. If you have thoughts that you should not be with your boyfriend, that's a good indication that you shouldn't. It sounds like you have a lot on your plate, and that he has a lot on his too. Perhaps both of you should concentrate on your own lives separately. That doesn't mean that in the future things couldn't work out, but perhaps now is not the time--he just left the military, and he has a daughter out of state. You have a son. You work. It sounds like you have other issues with your boyfriend too. You are 24! That's a lot!!
Although the popsicle incident was immature on your boyfriend's part, he was right in one aspect--he's not your son's dad. It's not his job to take care of or discipline your boy. Give yourself and your boy a break. (FYI: Someone who is a true partner will work with you on anything. You don't have to force it.)
My honest opinion--I don't think it's a good idea to move in a boyfriend when you have a small child. That sets you and your son up for bad things--broken hearts, for one. I would really suggest reading Dr. Laura Schlessinger's "10 Stupid Things Women Do to Mess Up Their Lives". Dr Phil's "Family First" might be one you'd be interested in too. I think those books contain pretty practical advice. Be good to yourself by taking care of yourself--take care of your spirit and your son's spirit. Start 2009 right.
I will pray for you.
D.