Husband not caring what I think to let an old female friend stay at my house while ping thru to go to P.A.?

My husbands old friend is coming into town to see him.(who he hasnt seen in 8 years) I have never met her and he invites her to stay a night with us and doesnt even ask me. Problem is, he's been hiding talking to her from me, and when I told him i didnt want her staying, he told me to get the F*** out. He holds her so high..he said the other night hed choose her over me. To him she is better than sliced bread. What should I do? Should I allow this..should I leave him? I just cant understand why he'd choose her over me. This has been an ongoing problem. He says they are like family ( brother and sister) does that give him the right to choose her over me and his children? I love my husband. Maybe I am over reacting. I know everyone i talked to said you cant bring another woman into the house no matter who it is because there are going to be problems. Some were astounded hed even think about letting it happen. Any answers would be of great help..from both men and women. Thanks!