My family's religion has gotten me really twisted up about sex. I don't participate in that denomination anymore, but it still makes me feel guilty when I try to or think about trying to have sex with my boyfriend. I'm worried about it effecting me later in life - what if I'll never be able to have sex because of religious trauma?
Unfortunately a lot of people are in your situation. It may take some time for you to be able to fully embrace your sexuality. For now, why don't you go over the pros and cons of sex as YOU see them. Write them out. Think about why you want to have sex. Then think about the ramifications you would experience because of sex. If you think sex makes you a bad person, then why would you think that? Break it all down into bits and pieces until you can reconcile each point for yourself.
In the meantime, perhaps you should meet with a clergy person whose views are more in line with how you feel now. Maybe talk to a liberal pastor or a Unitarian leader. Ask them how sex and faith interconnect, whether sex outside of marriage can be moral, and whether you should continue to feel guilty about your sexual activity. Seems to me you want to believe you don't need to feel guilty, but you've been conditioned to believe otherwise. If the guilt persists, either you can choose to abstain, or you can see a therapist and try to hash out your sexual inhibitions.