Can I leave the country if I’m pregnant with an American guy’s baby?

Let’s say I’m from another country and the whole reason I moved out here was bc a couple distant relatives living here wanted to help me get my papers in the US so I came got my green card and been livin here ever since. I met a guy fell in love, but turns out he’s a douche. Too bad it took me too long to see that because now I’m 20 weeks pregnant with his baby. We don’t live together I have my own place. We’ve been together for 2 years and he’s been cheating on me for months and I’m just really hurt. I miss my family, theyre basically all back in my country and I haven’t seen them in years. I’d like to go back to my country and have my baby there, but everybody else tells me that’s a stupid decision because if I had my baby here he’d be an American citizen and in the future I could get my citizenship too but I just hate to look at it like that. Like who cares I already have my GC and I’m not about to use my child like that. That’s just my opinion. I would hop in a plane right now not to come back ever if I could because I am just so hurt and emotional. But this whole thing is worrying me because I don’t want to go to jail for taking his baby away without his permission I just don’t want to live my life and my baby’s life depending on what he says is cool to do.