Sex with him or not?

I am recently out of a 2 year relationship. I am horny and I don't want to have sex with just some random guy.
I have kept in touch with my exboyfriend from a few years ago thur myspace. The other day out of the clear blue sky he asked me if I want to...

have a sex with him. He has a girl that he has been living with. I don't know her or anything about her. When I asked him if he was sure he knew what he was doing, if he would be ok after he cheated on her. He told me not to worry about him. He was just looking for a good time. now the questions is...do I have sex with him??? I know this sounds crazy but I really want to know what you think.

Right now there is one person who is a jerk...if you do this, there will be two.

Don't become the 'other woman' just for a roll in the hay. You won't only be hurting his girlfriend, you'll be hurting yourself and your own self-respect.

Be the bigger person.

Wow that is wrong in so many ways.. no offense..