I like this boy but he used to go out with my friend and shes still not over him?

If your friend still has feeling for him don't , unless you don't value your friendship with him, if she was over him fine. but shes not and seeing you with him can really hurt her. and to find another guy to go out with to get him jeolous, won't work and why would you consider on hurting another person using him in that way. if you keep doing that no guy will go out with you..would you like it if someone was seeing you to get another person jeolous, I really don't think you would. before doing anything ask your self if you where in there shoes.