Ever since I've dated my girlfriend (seniors in high school), she's been very touchy feely with her closest guy friend. When she sees him, she runs over and gives him a huge hug, kiss on the cheek, and sometimes will sit on his lap. If they have a class in the same building (private school=many buildings), she'll walk with him and hold his hand. For the longest time this has bothered me, yet I didn't say anything because I didn't want to sound jealous/clingy. I wouldn't mind if it were a hug, but kissing and holding hands all the time is something reserved for a relationship, not a friendship.
When we started dating, she told me how he has always been in love with her, although she doesnt feel the same way for him, and he said he could put that aside so we could date.
We got in a small fight (extremely small) about something dumb and later that I'm sure she told him what had happened. The next day she tells me that this boy asked her to prom and she said no. ***This kid knows full well that we would be going together, WE'RE DATING!*** At this point I realized that he still has huge feelings for her because he saw an opportunity where she wasn't thinking of me and decided to take the chance and maybe she'd say yes.
I respect her for telling me, because some girls would just not say anything. I am planning on talking to her about this whole situation about how I feel uncomfortable with the way they interact with eachother because I know his past feelings. I don't want them to stop being friends, I just want her to tone down everything and stop kissing and holding hands, it gives the kid the wrong idea and it bothers me.
How can I explain to her my feelings about this situation?