I am so sorry you are experiencing this pain. Please remember you are also hormonal so the pain is intensified greatly.
If you can, PLEASE, remember you must think about and care for you and that baby. I know you are hurting, scared, and angry but this will get easier.
Try to NOT think of him...think of you! Love you and that child.
My suggestion is not to look into what he is doing. I know it goes against every gut instict you might have, however, remember hes going to do what hes going to do, regardless of whether you know about it. Try to remain calm. Try to sleep and rest while you can.
Many hugs