About the looks, saw a documentary where is stated than on a scale from 1 to 10(ugly-pretty), one will mostly date someone 2 points above or bellow max, so in case your bf is a 10 in looks, that makes you a solid 8 minimum, that's well above average girl...anyway he shouldn't be saying that if he is a proper gentleman, tell him to stop this behaviour, maybe he is the 8 and you the 10, so out of pure insecurity he's trying to put you down, that's not ok. On the threesome, some couples do find it helpful to rekindle, minority though, you both need to discuss that. There are other ways, I find "false cheating" the most useful, it's when you "cheat" but it's with him, just that he'll need to act and change his name to be "the other". We humans are quite complex, so the only thing do do is to chose one aspect of your personality and exaggerate it when you become this "other" lover.