What's the problem?
He's just after a bit of action, and you can't blame a guy for trying.
If it's bothering you that much, ask him to back off. If he doesn't, report him to your manager. But if I were in your shoes and I had a woman making those sorts of offers to me, I wouldn't turn her down.
The statement you have made makes , you just as bad and in the wrong as the person doing this to her = both sad little men