Anyone else feel really guilty or ashamed if you want sex or afterwards?

I have C-PTSD from various sexual abuse. Me and my boyfriend have gone down to Falmouth for a few days, and we have been doing a lot of fun stuff, including dirty stuff. As I'm too embarrassed to initiate this sort of stuff, he usally does it but when I feel like I want to do something like this or afterwards, I just feel really bad for wanting it or I just feel so guilty. I don't know why, I just do. It doesn't happen all the time, mostly when I start or iniate stuff.
I always shake a little bit afterwards too but I'm ok with that these days, it's just I hate feeling bad about asking for sexy stuff.
Anyone have any ideas about this?