YANBU. Far from it. You have been really intelligent and sensible - you saw the hairs in the bathroom, didn't do anything hasty, but having seen them in both the bathroom AND the bed/pillow you sensibly broke up with him, and now you're protecting your health by getting tested. I think you handled it brilliantly.
By him not denying it when you broke up with him, sadly I think you were right about it all.
Well, what a stupid, stupid man. He had someone who loved him and was true to him, and he threw it away for casual sex. He'll have plenty of time to repent at leisure.
Meanwhile, you are a STAR! You know what you want and you won't put up with any of this nonsense from men. Better to be single for a thousand years than put up with someone who does this to you.
I've been single for a long time after a long marriage, and the more time you spend single, the less likely it is that you'll put up with a relationship that makes you feel crap, imo. So maybe spend some time being single? You don't have to live like a nun. I have a good male friend whom I sleep with sometimes.
What a rotten thing to happen right before Christmas. I send you cyber-hugs ((((SmilewithStyle))))
People who are in a relationship but sleep with someone else...there's something wrong with them, there really is. Especially when it's not a situation where someone is totally trapped due to kids/finances and has been neglected for years. Not that that makes it OK, but at least it's probably more desperation-based than down to psychopathy.
You're the normal one, OP, not him. There's something seriously wrong with his empathy levels or his attachment style to do this.
I have found that the quickest way to get over someone is a clean break. No contact at all.
I know you ordered at at-home testing kit, but perhaps you should go to a clinic for whatever tests aren't included. I also think that in-clinic tests for things like chlamydia and gonorrhea might be more accurate? I'd look into it and make sure you're doing the best thing for your health. Maybe you should take PrEp? Get an HIV test, anyway.
Better times ahead and better people to meet, OP. You're a winner for taking decisive action. I'm impressed!!!