husband says hes bi-curious and im... not sure how to feel

married 9 years. weve done a bit of soft swap stuff, mostly same room same bed, nothing crazy. last weekend after a meet in london he told me hes been thinking about being with another bloke. not instead of me, alongside. and like... ok. i love him. i want him to have what he wants. but theres a weird voice in my head going what if hes actually gay and ive been a stepping stone for a decade. i KNOW thats not fair to him and probably not true, the sex between us has always been mad good. but the voice is there. for the bi wives or husbands of bi-curious men out there how did you sit with the wobble. did it pass. and the practical bit, are there even mixed clubs in the uk where a BiM can play without it being a weird thing. everywhere i look its couples and single women only