My thanks to all who have contributed, with the possible exception of Summer Isle who seems to be addressing something specific and not the issue of friendship outlined in my first post.
The chances of reasonable meaningful conversation with X are not good just now, as the urge to "grasp them warmly by the throat" is very strong due to the distress that X has caused Y and that communication with Y is strained due to the climate of suspicion that has thus been created.
I am trying to decide if X is just terminally stupid and unaware of the consequences of their actions, and therefore has no idea of the extent to which this action has hurt Y and myself, or is a vicious, nasty, vengeful, spiteful person lashing out because life is not treating them well just now and they want to share the hurt they feel around
It is not the accuracy or veracity of the statements X has or is making with which I am taking issue as there is often an element of perception and point of view about these matters, that possession of the full facts by the parties involved might alter, but the backstabbing action towards a friend of long standing, who has shared and supported, and in their turn been supported, in good and bad times.
If you like it is less about the detail of this particular set of circumstances and more about the nature of a friendship and expectations one may have of ones friends in delicate and confidential matters, and thus whether this one is damaged beyond repair or recovery. This ( the positive posts above) is why I sought help here and for which I am grateful. Sympathies to 53, and KimC sometimes things get busy in everyones life, real friends turn up again and renew contact, arent you ever "very busy with living" and have to frantically remake contacts after a (brief) lapse?