You are too careless. Even if he/she kisses a guy/girl, you won't be jealous at him/her. We don't know if you trust him/her so much or she/he is worthless for you. We think you should realize if you really want him/her or not. You have to do it for yourself because it can't be just one lover in a relationship. If you trust him/her so much, then ignore this description and dont be that sure ;)