Should I date this guy or not?

Run far away from this. He considers you a " rebound girl". He was honest enough to tell you that he was with someone else, but apart from that, he would be in control of this " relationship" since you seeked him out.Your initial mistake was sleeping with him. Sorry but that's the truth.If he slept with you once- you know he would want to pick up where he left off.See it for what it is. Ask yourself : Can l do better -does he see me as desperate -......... what do you think?