"Dealing with a girlfriend getting hit on doesnÂ’t necessarily just apply to someone approaching your partner at a one-off social event. Sometimes you will find that one of their friends of the opposite sex suddenly reveals more desires than simply friendship. This generally comes from a lack of choice in that personÂ’s love-life.
This situation once again comes down to trust that your partner will keep you updated on the situation as well as a mutual respect to let everyone know where they stand.
You actually have a lot less to worry about in these particular scenarios. For someone to get to the friendship stage, having bypassed the creation of sexual attraction, it is very hard for them to go back and create it once they are regarded solely as friends. Furthermore, they are showing their own lack of integrity and attractiveness by hitting on someone they outright KNOW is in a relationship."