i feel like PTSD is ruining my relationship

hi! when i was fifteen i got into a relationship with a man who did not treat me right. he was physically, sexually, verbally, and emotionally abusive. i already have PTSD from a situation prior to meeting my ex boyfriend, so he really added fuel to the fire. i broke up with him at eighteen during my senior year! throughout the relationship i was raped and sexually assaulted multiple times. he was very into BDSM and so am i, but he would always cross my limit.

after i left him at eighteen i moved into college months later and wasn’t looking for ANYTHING at all i was completely going to swear off men FOREVER. i met a boy and he was just a friend at first that i found cute and sweet. this boy had voiced a crush on me and i immediately friendzoned him. however the more i spoke to him, the more i fell for him. before getting serious or even thinking about going out with each other, i told him all about my ex boyfriend and how he has to be patient with me and my traumas. at this point i started to feel PTSD attacks again, but this time about my ex boyfriend.

throughout my relationship with my boyfriend he has been SO patient and understanding. i am so head over heels for him. aside from a few flashbacks, our sex life is great! however recently we had sex and it felt too similar to this one situation that i always have flashbacks to. my reaction to being triggered was nothing like i’ve noticed before. ever since then i can’t look at him the same and im scared to be sexual with him. i over analyze every bit of our relationship scared that i might be falling into another abusive one. i just need advice if anyone has ever been in my situation before. why is my brain screaming at me and telling me that he might be abusive just like the last guy?! my boyfriend is so sweet and the calmest man ever. why am i thinking like this? i almost feel guilty??