i think my sister hates my boyfriend and i need advice

i’m gonna try and make this as short and sweet as possible

I F(20) and my boyfriend M(20) have been together going on 5 years this year, we met when we were both 15 and in the 10th grade. When we were teenagers we were dumb and stupid and snuck around (which i think most teenagers do at some point with strict parents) my mom was always strict on me and my boyfriend has a chill mom, so in order to see him when i wanted to i had to sneak around and i snuck him in one day when we were 17 and obviously we got caught lol, my mom found us and she immediately ran and told my older sister (my sister and i have a 17 year age gap) they also both found out that him and i were sexually active (my mom and my sister are both very religious and are the type that insisted that if i have sex before marriage then I’m a disappointment basically) anyway, we got through that, it’s been 4 years since then and my bf and i are much older, more mature etc. But my sister has never gotten over it, she holds this constant grudge against him and even said i must make sure he stays very very far away from her, anytime we have an argument she somehow always drags my bf into it and says i spend too much time with him and she’s not gonna sit by and watch someone that takes advantage of women (he obviously does not take advantage of me, if he did i would not still be with him today) it’s very clear she has a problem with him but she’s now influencing that on my mom too, i have no idea what to do but i know i’m not gonna break up with my bf, he makes me so happy and he’s my escape from my house and everything going on in it, he is the sweetest person ever and he has the most respect for me that anyone has ever had, (also side note i’ve never once spoken to her or my mother about any issues or problems my bf has had in our relationship, i keep that very private and between me and him and he does the same) it just sucks that my sister is so stuck on the past that she doesn’t even want anything to do with him. i don’t know what to do and i could really use some advice. thank you.

TL;DR: I (20F) have been with my boyfriend (20M) for almost 5 years. We’ve been through a lot, including sneaking around when we were teenagers and getting caught by my strict mom and older sister. My mom and sister both found out we were sexually active, and they’ve held that against my boyfriend ever since. Despite us being older and more mature now, my sister still has a grudge against him and constantly drags him into arguments, accusing him of taking advantage of me (which is not true or else i wouldn’t be with him). She’s even influencing my mom’s opinion of him. I don’t want to break up with him; he makes me happy and is nothing but respectful toward me. It’s hard because my sister can’t let go of the past, and it’s affecting my relationship with my family. Any advice on how to handle this?