Just wanna say straight up that this is a great subreddit and I really appreciate all the input. At first when I read this first comment, I was defensive, but I couldn't respond right away. I didn't have a chance to respond right away and it gave me a chance to reflect a bit on what you said and that behavior is disrespectful to my girlfriend and Jess needs to have boundaries. On to some more info though (I didn't want to share more than I had to but should have).
By handsy I mean that she likes to hug, and if she's excited to see you or excited for something you said she'll do something like squeeze your shoulder or put her hand on your back.
The specific situation that freaked my gf out was at my sister's bday party. Jess was invited, because she is like family as I said. We took a group photo and I was late to the group so I went to the front and lied down as a joke, then sat next to others in the front. Jess came over and lied across the laps of the people in the front for the photo. My gf was not ok with this, and was upset because most of the people in the picture were standing with their so's.
A couple months back Jess's husband and I pointed out to her that her doing stuff like that is off putting to people and affects her relationships with women. Of course she doesn't intend for that, but we said you need to watch yourself. Upon further discussion with her I told her that wasn't ok around my gf, or in general now that I'm in this relationship and Jess apologized and promised she would work harder.
My gf doesn't want to be around Jess at all and doesn't want to give her a second chance. Jess has been my friend for a long time and she's helped me through a lot. She means a lot to me as a friend and I am concerned that if I fold to this it will set a precedent for other friends she doesn't like (the others are men).
Friends aren't as big of a deal to my gf as they are to me. I have a lot of really good friends that I like to see, but recently I have spent about 80% of my free time with my so to make her happy. I just really want to try to find a way to make this work.