I'm sorry you found yourself here. My ex left me when our D was 6 months old. The one we went through surgery for him, IVF for me to have. He claimed no other woman. Well, there was for sure another woman. I could also tell you, my ex wouldn't have left me if there was another woman.

I am sorry, but I am 99.9% sure she is having an affair. I would lawyer up and fight like heck to get your 50% of custody.