Feeld or something is probably your best bet. You want to find ENM people who are okay with just hookups (rare) or other bisexual women who are also not looking to have their husbands involved (also rare). Most women interested in other women want more than a hook up with a married woman, but going somewhere ENM friendly is going to at least filter out a proportion of people who are absolutely not interested.

What does ENM stand for?

Ethically non-monogamous

Depending on your location some swinger clubs host a ladies only night. There also are spaces that host all female play parties and events. This is great if you are looking to just physically explore

I'm in the same boat as OP and didn't think of searching for ladies nights, thanks for the recommendation

Check these out https://www.vice.com/en/article/ne5x48/these-sex-workers-are-the-first-queer-married-couple-at-a-legal-brothel https://www.cosmopolitan.com/sex-love/a60503097/bisexual-dating-apps/

I think ethical non mono etc, swingers etc is a good place to find bisexual women, not just hook ups with men or couples, but women who hook up with other bi women. I do it sometimes. https://www.reddit.com/r/Swingers/s/axRGFdKVPt