A Threesome Would Be Awesome.

Talking to a work colleague it's become very apparent she's had sex with my husband.
Her description of her ex, plus some of the things she's said about how her ex used to fuck her with his large girthy cock, and some specific tattoos he has, just tells me my husband has indeed fucked all her holes.
Now normally that wouldn't be an issue as she's an ex. However when she's describing what they did together I'm usually tonguing her pussy.
We've been having a lesbian affair for over six months, and only a few weeks ago I began having her describe in detail how her ex's fucked her as I tongue her pussy and suck on her clit.
She has amazing orgasms this way, and to be honest when she's talking about what my husband and her did together, it turns me on incredibly.
Id seriously love to get all three of us in a bed together, but I know for definite my husband wouldn't want to revisit having sex with her. Indeed he wouldn't entertain being in the same room.
More's the pity, because I'd love to be licking her juicy c**t as my husband was fucking me from behind.