Being raised as a kid by a religious mother, I've always been told, or been lead to understand, that being sexual was ok only after marriage and it shouldn't happen with multiple people...

I'm 22 years old, and I still feel ashamed about being sexual. I feel that I do something wrong when I masturbate, or I am scared to go into relationships because I've never been able to keep a long term relationship and I feel like if I slept with more than one person, the next person that would come along would judge me for how many people I've slept with and wouldn't love me anymore..

Ofc I don't judge other people for doing this, I just judge myself. 

Now, I am not sure if this is a BPD thing, but does anyone else have this problem? 
How do you get out of this mindset? I've tried over the course of my lifetime to feel less ashamed of being sexual in any way, and even though I don't believe in a God or anything, I still feel like I'd be doing something wrong. 

Help T_T