Glad to hear is was helpful then.
If all of you were sitting in a waterbed, him FLINGING himself on it could send the rest bobbling about on the waves he made. What one does, could affect others.
If he's trying to build a 3 person polyship of some kind, he could remember he's not the only player. His willingness to participate is not the only willingness required for it to go well and succeed. His skills/ability to participate are not the only skills/ability required. There's 2 other people that have to get on board with their "willing and able" for this to fly WELL if the shared goal is a harmonious, healthy open relationship model
of whatever flavor you all are trying to co-create for yourselves.
Is that even a shared
goal? He was not taking the trouble to ASK and find out (with you) and he's just pushing and not respecting her "No." (with her). All players could get on the same page first.
Maybe reading about polymath
and how one mini relationship inside the larger polyship can affect the others could give you more perspective too.
I hope you do find peace and clarity as you wish.