What is up with this guy?...

I'm in a long term relationship. I'm 18, he's 20. My boyfriend has this friend who's like in his 30's. We've been hanging out with him quite a bit. I just met him. He told me he was like surprised i was with a guy like my boyfriend. Well this one night i was drunk and my boyfriend wanted to go hang out with him. So we went cruising. Everything was fine. But literally this guy is married with a kid and always talks about leaving his wife. He said he won't yet because he has a lot invested. I met her yesterday and i honestly felt so bad. Well anyways i went home yesterday. My boyfriend's friend keeps hitting me up. Telling me I'm a cool person. He asked if he could come over and we could have a beer last night. I said I'm going to sleep. And then he said he was just joking. Now today he was supposed to do something with my boyfriend but my boyfriend is probably sleeping because i haven't talked to him all day. So he just asked me if i want to hang out with him an have a beer and go fishing. This guy is attractive but like i would never cheat on my boyfriend. Idk i feel like he has something on his agenda....I'd be a little weirded out if one of my girl friends was texting my boyfriend a few times a day asking to get together......what do you think?