Partner has a really close girl mate

I'm so sick of this girl constantly interfering in my relationship with my man. We have been through hell and back over the past 2 years and they talk continuesly. She asked him to go for dinner tonight and he cancelled it acouple days ago but than we had an argument this arvo now I'm left at home alone while he's out and won't talk to me. I'm worried something's going on between them. He says he won't come home.