Namechanger, just in case friend is an mner.
Right. H and I split up last december. He was deeply depressed and had become impossible to live with. I had to protect me and the children from his mood swings and ultimately emotional abuse of all of us.
A good friend of ours supported me through all this. She was great to talk to because I knew she knew h so well too and I didn't want to vilify him. He was an ill man who behaved terribly, and although it was his responsibility he is not a monster.
She knew what we went through and how it was affecting my own mh. After he got to me again in April she was there for me and comforted me while I sobbed and screamed. But I did one thing I do regret. H was staying in my home while I was away. He sent me an email saying he was going to go out drinking (not a good thing, doesn't drink because it brings out a nasty side in him) and wanted nothing more to do with me.
I panicked. He was in my home, he was going to bring his new friends (who I did not know) back there. I feared he would do something to my home. So I asked my friend to call him. She agreed. I wish I hadn't.
He assured her it was a couple of drinks with the lads and no one would come back. I told her he was lying. She felt uncomfortable as she could only go by what he had told her.
I called her the next day to apologise and say that I had thought things through and had calmed down (still with me?). She said all was fine and assured me that above all I was her friend, and that much as she loved h too her loyalty lay with me.
Of course h did get completely hammered and had his mates stay over and sleep in my bed, but that's by the by.
I didn't really hear from my friend for months. We don't live near each other. I sent her another long email apologising and thanking her for all her support. She sent a short one back not really saying anything.
Fast forward to a month ago. H and I are friends again and go to visit them (spur of the moment, happened to be in their area, a long way from where we live). Everything seems fine, and i begin to think i was panicking about nothing. We get very drunk and get onto the topic of what happened. I say I'm real sorry (again) for putting her in the middle like that, she says it felt very uncomfortable, I explain I was desperate but shouldn't have asked.
She then says that she's pleased me and h are getting on so well, but that given his illness she's decided that h needs her more than I do, and if things turn sour again I am strong enough to do it alone and they would stand by h. I was a bit 
I said I would never ask her to choose, and she replies that she knows I wouldn't and she'll always be there for me if I need to talk, but that that is the decision they have made.
She then went to bed.
Next morning we left early. But she seemed to have no memory of what she said (very possible she was very drunk)
But I remember.
I want to point out that I have set up a very strong support network for h and his depression is now controlled completely through meds and counselling. He is not alone and has several friends he can now turn to for help as well as his gp etc.
She's one of my oldest and closest friends. And I feel gutted.
So, should I forget it? Should I pretend it never happened? Should I Talk to her about it?
H is mortified. He says as much as he loves her too he knows she has always been my support and that he has his own friends to talk to.
Please be gentle. I'm Not strong enough to hear that I'm whiney and she's just had enough of me. Although that is probably the truth.
I've been there for her too btw. It's not all one-sided, but it has been more about me lately. H put me through hell, he really did, and although I can forgive him (not get back together with him, but be friends) I find it hard to accept a friend who knew what I went through is declaring her loyalty to him instead of me.