From what you describe, it sounds as if your relationship has got into a pattern that really is an emotionally abusive one. You suspect something is wrong, you look for proof, you feel you find it, you confront him and then he either denies it or says it won't happen again. You tell me that when he does actually agree he's been in touch with other women, he also tells you that it meant nothing. But, I suspect it means everything to you because he repeatedly breaks the trust that you're entitled to expect from a committed relationship. There's nothing wrong with open partnerships but to make those work, each person has to be in full agreement that they want to run things this way. For you though, it sounds like you didn't sign up to that and are constantly on the alert, and as so often happens, ending up almost playing detective, trying to second guess every word and action. That's exhausting.