The best friend boundaries

Hi.. im not really good at expressing my feelings much but this has got to me so much I find myself having nightmares waking up crying and desperately want answers. . So here goes... my partner and I have been together for 3 and a half years now, our relationship isnt perfect but we have been to hell and back together and have a very strong bond. About 12 months ago we decided to pack up and move to the city where he grew up, its a great city and I loved the idea. Unfortunately though things have taken a turn, he got in contact with his best friend (which is a girl) from his childhood. I have no quelms with this as I gave him space to go catch up with her as I trust him with my life, and she is married with 3 kids. Everything was fine till about 2 months ago when in a druken rant over facebook she addmitted she was in love with him and has been the whole time, he knew it made me uncomfortable and told her he would forget she said anything as he didnt want to make things awkward and still wanted to be friends and she agreed she was sorry she said it and would not bring it up again. Then about a week ago he went to see her again while I was at work (which he told me he was going to do as he is very honest and I trust him), just to hang out, her husband was home and her kids, they had lunch together and she started eating stuff off his plate. Then they went back to her house where she flirted with him most of the afternoon to the point where her husband (feeling self conscious) went to bed early. Then she immediately rushes her kids off to bed and attempts to get my bf drunk so he couldnt drive and had tostay the night ( thankfully he didnt drink and told her he had to go as I would get mad if he stayed out too late) before he left though she was resting her head on his shoulder, bending over in front of him, putting her arm around his shoulder and as he left she even yelled out 'I love you'.. I have tried to tell him that she is pushing boundaries of way too far and I dont know how to deal with this, I told him how I feel and he said he would never say it back to her as he doesnt love her, and he says he still wants to be friends and feels she is destroying their friendship, he seems to think the best solution is pretending to be oblivious to her gestures and carry on making a point he just wants to be friends.. but she even jokes to him asking if im jealous. I dont want to come between their friendship but I cant jeopardize my relationship... when shes sober she says she wants to meet me and we should all go do something together (her family and ours) but as soon as shes drunk the truth comes out and she says she hates me and never wants to meet me and im not welcome to come with them or come to her house. Please help I dont know what to do from here. Regards Confused and Dishearted.

Your partner is the one who needs to act; he needs to cut her out of his life (the one you guys share together) for some very real reasons. The fact that he has used you and your possible angst for staying late, as an excuse not to drink with her should have you more worried than her actions because, to be frank, he should know better than to put himself in that situation AFTER her drunken face book rant and he should recognize her as a threat to his union with you. He is jeopardizing everything he has with you for the sake of a friendship which has become basically unhealthy for everyone involved. You need to realize that when you state that you don't want to come between their friendship, the real fact is, is that there shouldn't be anything or anyone coming between your relationship with your partner. Absolutely nothing. Your 3.5 year relationship should be one of predictability and while you trust your partner explicitly, his actions are starting to erode it. You need to tell him this. It's plainly obvious that your partner's best friend views her marriage as a sham but she has no right to ruin yours with her actions. Your partner needs to step back and recognize this. He needs to take his thoughts further when he states she is destroying their friendship, he is actually allowing her to destroy his relationship with you. You should be his priority...it's that simple. Sure, alcohol doesn't lie, but the real issue is your partner's 'blindness' and loyalty to a childhood friend who has become intrusive and damaging. Sit your partner down and tell me direct where he stands with you and your relationship. His future actions will determine how much value he has for you and your relationship together. I'm sorry, but if he continues to interact with her, then you will have your answer.