Woke up to my (20F) boyfriend (20M) trying something sexual on me, need advice

I’m reaching out because I recently had a very upsetting experience and need some advice. I woke up to find my boyfriend putting his dick in my mouth at 6am, when I was exhausted. I didn’t say no immediately; instead, I just let it happen to get it over with, though I showed I was visibly uncomfortable. This situation is particularly sensitive for me as I am a survivor of child sexual abuse, a fact that my boyfriend is aware of. After the incident, when I brought up how uncomfortable it made me feel, he responded that I should have just said no.

I’m hurt and confused because there was no opportunity for me to give consent initially, and his response feels dismissive of my feelings and past trauma. He brought up maybe doing it before but I can’t recall specifically saying it’s okay with him. I’m struggling with how to address this situation and ensure it doesn’t happen again. Has anyone here dealt with something similar? How did you handle it? Any advice on communicating the importance of explicit consent and understanding in a relationship would be really helpful.