Where has he been all this time??? How did you break up?
This time he will infect you with an STD thats when you will come to your senses. How many women do you think he been with since he left you? Grow Up!!!
Do you still want him or you just want him to use you for sex???
It really depends on the situation I think. If the couple broke up on good terms and are still in each others lives then I think that's ok. But if they broke up on bad terms then that doesn't sound like a good idea.