My husband of 15 years has always been faithful but i caught him....?

having private conversations with a female they where playing poker then they switched to instant messenger then i caught it had a fit and messaged her as she played poker online to leave my husband alone and that since she knew he was married and that his wife did not like it she should have stayed away from him well they stopped well so he said but my husband stormed off and left did not call home for 3 days worried me and the kids then said he did not want to come home but he did he lied about his where abouts then he was gone a total of 7 days he came home and was real nice and kissy pooh and the next morning he told me where he went to visit her and it was not what i was thinking he said he became friends with her boyfriend she told me she has no boyfriend and he was just in the area which was 1000 miles from home we are living on a fixed income my husband is real sick and is going to have his foot amputated he is so making our life a living hell what would you all do i feel he cheated well he cannot get an total dead there but you do not have to have to cheat i need some advice i am heart broken my husband can be a mean abusive man any advice will be appreciated thanks all