Grandfather in law says dirty things to me

My boyfriend lives with his grandparents, were both 17 about to be 18 and have been together for a while now. His grandfather constantly says things that are inappropriate, saying things to him on the phone that are sexually suggestive about me and my boyfriend seems uncomfortable and hints at him to stop. I don’t think my boyfriend realizes I hear these things as often as I do.

Once I went over to his house and his grandfather told me that if I decided to come over looking the way I did, I might as well stay in the basement with him (the grandfather) for the night infront of my boyfriend and my bf told him that wasn’t ok or funny. He waits until my boyfriend is away to put his arm over my shoulder or get close but I assumed it was because his family is the hugging type, they show a lot of affection with hugs.

I was sexually assaulted about a year ago by someone I was “friends” with, and I was sexually abused by an older male family friend already. I don’t feel comfortable with the inappropriate jokes and i try to make it obvious without offending anyone that I don’t think it’s funny. I’ve talked to my boyfriend many times and i think he’s beginning to understand how I feel but he’s In the uncomfortable position of not making his grandfather angry, but letting him know that’s it’s NOT okay. The grandfather openly has asked about our sex life, and when I’m not around speaks to him like I’m a blow up sex doll, and my boyfriend hangs out with me and spends time with me because I’m a bag of holes which is not the case, and if it were to be I’d be long gone. Am I overreacting? I need perspective on this. He called him a few hours ago and said “Just come over once you get rid of that chubby (erection).” Am I being a prude or taking it personally? I just don’t think it’s funny.