I have a similar "tried to cheat" story. I was dating a guy for a few months when his roommate moved away and he had nowhere to go so I let him stay with me for a bit (2 weeks at this point). I went out of town to visit my mom and he was super distant the whole time. When I returned wouldn't even pick me up from the airport because he said his buddy was picking him up to go drink and watch the game and he couldn't drive. So I get home and his car is gone. He comes home a few hours later (in his car) totally wasted. Tells me he was at the strip club and that he's not ready to be in a relationship but wants everything to stay the same. So basically wants me to act like his girlfriend but without any of the responsibility. I ask if he's talking to any other girls or if he wants to see other people and he says no. Then hits me with the biggest red flag of a statement I've ever heard "why would I do that when I have you?" I knew he was lying but pretended to believe him. We went to bed and in the morning I woke up with this nagging feeling he was lying to me. So I did something I swore I'd never do and I looked through his Apple Watch. Sure enough there were dozens of texts to other girls (all dated during the three days I was out of town) trying to hook up with them. From the texts his pursuits didn't seem fruitful and he got shot down multiple times. But I was livid. Having bought the watch for him, I took it and left while he was still sleeping. Turned my read receipts on so when he woke up and couldn't find the watch and texted me, he'd know something was up. A few hours later I get a panicked message "babe I can't find my watch." I don't reply and the texts get increasingly more panicked and it's becoming clear he's aware of exactly what is happening. Calls me 20 times, I don't answer. Finally I reply and tell him to please leave my apartment by the end of the day. He tells me it wasn't cheating because "he never actually hanged out" with anyone because they all denied him. Ok so you were going to cheat but you couldn't find anyone willing so you didn't and that makes it ok? Fuck off.