Take it from a seasoned queen…for your sake you need to let him go. As Maya Angelou said “When someone tells you who they are, believe them.” Honestly…he wasn’t thinking about you when he went on that site and hooked up with whoever. It’s not like you two had discussed an open relationship.
Had he came to you and explained why he wanted to have sex with other people and you both agreed that was okay you two could have set some boundaries and rules for that kind of arrangement. But discovering that he just flat out lied speaks volumes about his priorities. And I’m sorry to say that you ain’t one of them. Too much going on to just play Russian Roulette with your health to allow him to stay in your life.
It’s gonna hurt. It sounds like you really love this guy, but trust me..there’s someone out there who will give you the love and respect you deserve.