stuck in the middle

The back ground
I'm single and have been for a over a year now due to my own choice. My best friend and her partner have been together for 9 years and I regularly meet with them go out drinking ect. They have 3 children together and he has 1 from a previous relationship. although they both have tempers at times they get on with it . Her partner and I get on well and never thought anymore of it even when he has made the odd comment before ( usually when he is drunk). One night I confessed to him that I felt attracted to his mate and was shocked when he told me that his mate felt the same about me but was shy he said that my bestmate his partner knew this. Well as I thought at the time nothing happened of It as we didn't meet much and the only place we did meet was their house, there could be a reason for this but will explain further down.

Last few days.
My bestfriend left her partner and went to her mums, I knew they had been argueeing the last few days but I try not to get involved she took the3 children with her and I knew within 10 mins of her leaving. Her partner was on the phone telling me that she had left. He was pretty drunk and angry at her but said he also had enough....... This is when he started saying come on let's hook up (rude comments ect) I didnt as I would never do this to my friend for starters and also I don't look at her partner in that way. Next day I spoke to both of them on the phone my bf still at her mums and he was at home. By the time I had finished work I had several messages from them both, she asked me to go round and see if he was there that the house wasn't smashed up and that he wasn't drinking. When I got there was suprised to find him completly chilled and no alcohol in sight. I stayed for a coffee and listen to him talk. As everyone says there are 2 sides to the story. As me and her partner was talking his best friend was brought up and he told me what my bf had said to him she's too old for you, she is a mum,why you wanna go with her ect. I was shocked to say the least I always put it down that we never really spoke enough to start anything. Next day her partner contacted me about a car his mate was selling and asked if I was interested so I met up with him after work again. While waiting for his mate to bring the car over he we talked again about all sorts and how he had spoke to my bf that day but how he still wanted to f*** me because in his eyes they were done now. I laughed it off and told him to get agrip. He hadnt been drinking this time and even went on to ask me why I wouldn't ..... He came out with you think I want to f*** you to get back at her. I quickly left and spoke to my bf that night abouthim missing the kids and that he aint drinking and suggested they talked not mentioning the passes he made as even tho he said that its not to get at her I believe different. So that night she rang him and went home........today they are carrying on like she never left. So what do I do? As a friend should I tell her what happened or leave it and is she even really a friend if she said those things about me to her partners mate knowing how attracted I was to him? Did she say those things because she thought he was atttractive too. Confused to say the least and not looking forward to seeing her partner again either now.

Would value anyones take on this
Thanks in advance