Originally Posted by
Katetheo 
With my friend she knows what's going on and is also someone else who thinks I'm best off without him. She won't understand if I break contact but I'm going to have to. I can't be at her beck and call 24/7 and also it would be so wrong to support one alcoholic and not another xx
Well, there's "support" and there's co-dependence/enabling. I'm not sure how close this friend is, or what you've tried in terms of setting boundaries with her. You could provide support/encouragement and maintain a friendship if she respects your boundaries--which should include not being available 24/7 for drunken phone calls.
You might try that, if you're reluctant to cut her off completely. Cutting off your ex is a different story--you are more emotionally enmeshed with him, and you will have a very difficult time getting on with your life as long as he's in it.
There's no rule that says every relationship has to be the same. Boundaries that work with a friend might not be enough when you're living with someone.
There's certainly nothing wrong with ending contact with your friend if you feel she's toxic to you, or you don't want to go to the trouble of trying to set boundaries with her, or if you've tried and she consistently disregards them. Just suggesting you don't HAVE to cut off contact with one person just because you did with someone else.