TRIGGER WARNING SA TRAUMA

My daughter was SA by my husband for over a year before she told me. He is in prison and we are divorced. Its been 5 years. Ive known my current boyfriend for 20 years. He triggers me occasionally. He smacked my other daughters butt. (They were smacking eachother in the back playing around with good night hugs and she turned around and he smacked her butt) I got so upset. He hugs her longer than me (weve been.together 5 yrs and live.together. she calls him stepdad). How do I tell the difference between a gut feeling and jealousy and being triggered bc of my ex. If I mention it to him he gets super offended. I know its rude but I never thought my husband of 12 years was like that. How do i know i can trust my boyfriend. Im constantly worried about him looking at my daughters that way. Especiallysince my oldest is an adult now. Help me. I feel so awful. Younger one is a teen and not weirded out or uncomfortable and she likes him. So is it just me. EDITED TO ADD: Again weve been friends for 20 years not like i just hurried and got with some guy i didnt know. Its not like he hugs her excessively, just a good night hug. Also she slapped him in the back first its like a good night kind a smack on the back as part of the hug. I dont know how to explain it. Myself as well as my daughters have been in therapy. I know its not typical to be jealous of my kids but unless youve been through it you dont get it. My therapist says its absolutely understandable and we are.working through it. I trust my counselor