I guess the only way to find out is to start the thread.
I don't think it would be made a sticky though - I don't think sticky threads are used very often and probably because there are so many useful long running threads that if every supportive thread was a sticky there would be no room for current threads.
You mean one thread for everyone to post on? It'd get far too confused, and much easier for people to troll and SOs to find.
I don't think the Relationships board needs more rules to divide up where you can post based on the problem you are having (as you've mentioned EA, cheating, and domestic violence). Everyone has a right to their own thread with advice or suggestions specifically to them. We all can read those threads, and if the info applies, we can take what advice is offered. I would find one long thread confusing and difficult to follow with all the different people posting different problems.
Thanks for suggesting this. As ClashCityRocker said, it's not something we'd be likely to sticky, but you are very welcome to start such a thread and see what the uptake is.
We do have plenty of long-running support threads covering various subjects within Relationships - such as the 'Stately Homes' (survivors of dysfunctional families) ones, the Brave Babes Battle Bus threads and indeed the Hobbit's Bar ones, the tagline being: This is the place to come if your marriage/relationship has come to an end and you are struggling to come to terms with this. It is a place to vent, ask for advice, relate to others in the same situation, take a break and have a laugh, whatever.