19 year old virgin?

Hey y'all. So I have this thing where I need a guy to respect me and such before I will have sex with him. Reason is I've dated many guys who dumped me because I didn't have sex with them and I want the guy to like me for me. Some days I just feel like saying "screw my values and stuff" and just do it. But I'm also really insecure about my body because it's my first year in college, I'm a STEM major, and I haven't had time to go work out. Any advice?