I'm really sorry that you are in this difficult position.
I think it is definitely possible for you both to keep your relationship with BB if you and AA break up.
But that depends on how badly the break up goes, if it happens, and how likely the two of you are to stay friends. If you two are at war, that will obviously put BB in a very difficult position.
I would suggest that all three of you have a sit-down talk. It's going to be unromantic; but you need to put back-up plans in place. Sometimes the practical "what ifs" can be just as stressful as the actual relationship breakdown.
I definitely understand financial restrictions.
The three of you could sit down now and agree on things like:
- if you and AA broke up, would BB actually want to live with either of you?
- if not, could you all rent rooms somewhere else?
- if BB wants to live with one of you, who would she like to live with?
- if BB can't choose; could you literally toss a coin? or decide between you and AA?
- if you're committed long term and both really want to live with her, and her with you, could you even consider the idea that BB lives with you for a year, then AA for a year? if renting?
- if you or AA move out, what do you need to start doing now? can you save for a rent deposit? how long would it realistically take?
- is living together in a bigger place an option?
- could either you or AA afford to move out very soon, even if you're in counselling, to take the strain off?
I would also suggest that you both keep BB out of it as much as possible. It's obviously not fair for BB to have to pick sides and perhaps you can all communicate that together.
It sounds like you feel considerate towards AA and that is nice to see.
I do think that couples counselling is always worth a shot... but ultimately, there's no point staying in a relationship that doesn't work, just for financial reasons.
In terms of there being an awkwardness if you do break up and one of you has to wait to move out... I would say it's very similar to a mono relationship break up. You just have to try to be polite, get on with your own business and move out as soon as possible.
In your triad situation, it would be pretty essential that you each kept your relationship with BB considerate... i.e. literal things like each of you going out once or twice a week to give the other two time alone; BB having an outside-the-house date with each of you; not having sex when the other is around, if possible, and not being draped all over each other in front of the other partner.
Either way... if it is possible.. I would suggest that all three of you start saving up so that a move can be made if necessary... it might actually take some of the stress out of the situation.
I hope that you can work through you decisions in the way that causes the happiest situation for you. Good luck.
Me: (30f) open poly
Serious long-distance relationship with GF (40f)
Casual FWB with Descartes (27f)
“Peace comes from within. Do not seek it without." ~ Buddha