HELP! My boyfriend might be cheating.

Okay so I just saw him this weekend and everything was very good. We talked cuddled and you know. We did the usual things we usually do but after Sunday, when he hung out with his friends, his demeanor suddenly changed. I usually just leave him alone whenever they’re hanging out but he texted and asked for his ex-bestfriends number/snap to talk him and he wouldn’t say why. Mind you this ex bestfriend was a manipulative thief and he tried break me and him up but even after pointing out that they’ll never talk again, he himself reached out. I asked both separately what’d they talked about the next day. My boyfriend just said nothing meanwhile his bestfriend sent me screenshots of them talking about car races and going to AA meeting which was great. Then the past 2-3 days, we made no real contact and just snaps here and there. He usually makes time and call me everyday considering he travels for work most of the time. Now he goes home for 5 minutes and go to a random house down the block from and he doesn’t leave until morning? I don’t really know who lives there or why he’s there. He didn’t call or text and he’s been acting odd. He would just say he’s busy. I’m really confused and don’t know what to believe. We have gone through the same experience before but I left him last time without knowing it was due to depressive state and self issues. I don’t want to make a mistake and just leave him like I did last time but I also don’t want to ask.