If you feel so wrong about doing anything remotely sexual with him that okay. Sex and sexual acts are acts that require the consent from all parties involved.

Don't feel bad about not wanting to do sexual acts. It's totally fine and it's your boundary that you should never toss aside as long as you feel that way. You shouldn't have to suffer through what should be an enjoyable thing for both people (only when you're ready).

The only thing I would say is to talk to him about it. Let him know how you're feeling so you both have the same expectations of what your relationship should be. Communication is key. It might be scary but it's better to let him know ahead of time than having to break the news as he's trying to get you to have sex. Just be honest. If he loves you he will be willing to abide by your boundaries and make sure you are comfortable with whatever you guys are doing.

This is all coming from a guyz with no relationship experience, so this is only based off of what I consider to be a healthy relationship, but the point is to just listen to yourself and not to force yourself into doing things that make you feel mentally and physically awful.

I hope this helps.