Reasons why playing with fire is dangerous

In preface, I am entertaining the notion of being involved with AC again. This has fallen into my lap, as it often does, and I'm not resisting too well.

1. He is a player.
2. He will run away after the conquering.
3. He will make promises, break them, and fail to answer/ return my calls.
4. I have much better relationship potential with JS.
5. AC will demand monogamy, even though he will not practice it himself.
5a. He will guilt me into feeling bad about dating other people/ cause me to end a good relationship.
6. He will lie or omit important truths.
7. He will keep me waiting and will make me disappointed.
8. The sex wasn't good before/ he was an asshole about it.
9. Most likely, I will have to sneak him into my host family after hours and sneak him back out.
10. I will get less sleep because spending time with him leads to lots of drinking and many late nights.

Reasons why I can't resist-

1. I am not over him.
2. He's a really cool guy.
3. Fantastic conversation, jokes, etc.
4. There's a certain lure about dating an English musician.
5. My ego.
6. There's a challenge here...