Vent: Cheating maybe? Probably..

I’m a stay at home mom and I’m pretty sure my SO is or has cheated on me. I don’t know what to do.. of course he is denying. He works out of state, but works from 6am-7/8:30pm and we are usually on the phone throughout the day until we go to sleep. I don’t get how he would have time. He is home for the weekends.. we recently had a threesome with another woman, but she tested negative for chlamydia. He had a DR appt on the 18th and tested positive for it. I’m in denial about it because I don’t want to believe that he would actually do this, but obviously the proof is there… could it be a false positive? Ugh.. I don’t know how to leave..