Would u stay or leave

I am so annoyed by this whole situation not only that I’m disgusted I feel like I need to vent I’m losing myself and it’s becoming overwhelming for me, I’m a new mom I had my daughter 7 months ago my child’s father has a potential baby otw we’re in a relationship and also live together it’s so much he has done last year that I just cannot forgive him for yet I can’t even forget it. I’m hurt and continuously hurting I just want to be happy! February this year he tells me the girl he was cheating on my with last year is telling him she’s pregnant well here is the next part she’s due in JUNE so he reached out about dna testing yesterday and she tells him “it’s no need just sign his rights over.” it’s stressful Bc he is trying to do whatever to keep us together but I can’t it’s so stressful a couple weeks ago I found out I was pregnant with our second not even knowing .. well I lost the baby two days later after finding out over stressing. I am angry upset overwhelmed and tired I need advice I feel like i can’t even be the mother to my babygirl Rn really stuck in a hard place Bc Ik if I just call it quits n focus on myself I can fix my worries just like that! but fighting for my family is what I’m trying to do Bc it’s everything I want but I can’t put the past behind I’m constantly knowing I deserve better. Just feelslike so much with him forcing this shit to work and me staying Bc I wanna try