Yeah, I came off as a major asshole there...Mainly for assuming that you were looking for sympathy. My apologies.
She wasn't looking for sympathy.
Take a deep breath every time your mind trips the my life is all messed up thought. It is not.
The thing is that sex releases a lot of drugs in your brain. Good sex releases even better drugs. But they have a reason, one is to like sex, and the second is to help you form a bond with your partner.
If it is just casual sex, or sex for these happy feeling drugs you have to mentally struggle with the bonding drugs in your brain. It makes sex a big deal and can get you to stay in bad relationships. I know this is a highly analytic answer, but I do mean it to help.
This is why most religions focus on sex after marriage to use the bonding chemicals to help sore up the family structure rather then deal with the hell of casual sex within your brain and relationships.
I'm sorry that things feel so messed up for you, but remember it is a feeling. Most guys are not trained in our society to handle sex as anything more then a score, a good time drug and notch on his bed post.
You are going though what many have and will do in the future. You may find it best to just cut of this guy completely. If it is no big deal to him, and it is to you, then it is a big deal, find someone who agrees with you and shares your values to hang with.
Also in high school it is DAMN hard to do this. In college it is a whole different world, you will only be around people you choose to and dealing with subjects you chose to, if only because you had to for your major.
I'm really late to the discussion, but sex is an emotionally involved act. That is, you can't have sex and not let it involve you or him in some way, so he is lying to himself.
It certainly raises a big, big red flag.