Mojo, the fact that you feel this way after being with these men is a sign that they are not the right men for you. (And also that your ex wasn't either.) When you leave the presence of Mr. Right, you should not feel like the scum of the earth. You should feel like a smart, pretty, sexy princess/Nobel prize winner. Use these feelings to help you sort them out.
Also you're not a bad GF. You're a perfectly wonderful, normal woman who is capable of a close, fun, sexy, intelligent relationship and any guy who chooses to criticize you because HE is not comfortable is not worthy of your attention.