Husband had sex with my sister

Ok... I have never really talked about this but i need to know how to deal with this. When i was 15 and my husband was 17 we were boyfriend and girlfriend and took a break from eachother for a bit well my older sister and my boyfriend (now husband) had sex we got back together and when he told me i hated my sister for a long time and thought he was disgusting but i loved him. What was sick was i remember sitting on his bed one day after school and this was like a week before he told me and we were gonna do stuff and i wasnt to experience with sex and oral sex but i did some oral things to him and we were talking about how to do sexual things and he said yea i heard your sister gives good head. I dont know i cant let this go i am now 19 and my husband is 21. I started talking to my sister about a year ago but hated her for a long time. It will be so okward to see them in the same room together i think all i am going to picture is them doing what they did it really traumatized me i cant let go or get over it and i am afraid if i started seeing my family more and seeing them socialize or talk i know will make me mad or what if they start talking and have phone sex? or have an affair? PLEASE POST WHATEVER YOU THINK I NEED HELP WITH THIS