It is wrong to be possessive.
Yves' girlfriend meets a new group of friends and starts to spend a lot of time with them and less with him.
Yves wants to spend more time with his girlfriend.
Yves asks if he can tag along with his girlfriend and meet her new friends.
Yves tells his girlfriend that she has to choose between him or her new group of friends.
Yves' girlfriend introduces him to her friends and is happy when they seem to get along well.
Yves' girlfriend gets upset about how controlling he is being and breaks up with him.