Need help and tips to not go back with my boyfriend ..

So I been very stressed and confused with my relationship a part of me wants me to be with him apart of me doesn’t we been tg for almost 2 years now he has cheated on me with his ex girlfriend and turns out she got pregnant and says it’s his but he says it’s not his .this happemed a year ago and through out this whole other year I just will be happy for a few months but then worry if fhis is his baby and if he will eventually leave me its so hard to not text him or see him I try my best but always end up texting him and going back to him but I’m at a breaking point and I need serious help it’s not healthy anymore I don’t trust him but I do love him but I just think it’s time to let go but it seems super hard for me to do