Unfaithful partners? Stress at the end of pregnancy?

How many people found out their spouse was cheating on them during pregnancy? I am 37 weeks and just found out my husband has been cheating for two years. We hit a rough patch back then and my best friend noticed and manipulated him cause she turns out hated me and wanted what me and my husband have/had and convinced him that everything I did was because I hated him and I wanted him to be miserable when everything I was doing is cause I knew what was happening like I suspected it but convinced my self I was being paranoid and she wouldn't do that to me. She's a master manipulator and I knew that I just never expected to be one of her victims. Turns out she also slept around on him with one of his best friends for no reason and he thought maybe she was doing that but refused to believe it until I showed him receipts and turns out the only reason I knew according to her was so I wouldn't suspect her and my husband. Me and my husband are trying to work it out we've both blocked her on everything and I'm so scared this stress is going to hurt my son but I don't know how to not be upset and handle this and be ok for his sake I can't eat I can't sleep I'm barely able to stay hydrated cause I've cried to the point my eyes refuse to produce tears.