I let a girl eat out my gf and then she watched us fuck [mff]

Last Sunday was my gf, abbys birthday and she invited some friends over to drink and stuff. Blah blah.
One of abbys friends brought another girl with her, Kelsey, that we’d never met before. 20 minutes into hanging out Kelsey and Abby and me are all hitting it off, with the two of them not so subtly flirting with each other. I should mention that this is not normal for me and Abby and have been strictly monogamous our whole relationship. Anyways, the night goes on and Abby is a little too wasted and goes upstairs to our room to lay down leaving me and Kelsey hanging in the living room. Kelsey keeps telling me things like “you’re gf is amazing” and “she is so awesome” and I can see this lust in her eyes. I start trying to get to what I know she really wants to get to, and just say “I would love to see you two kiss”. Kelsey then asks me if I would let her eat Abby out to which I reply with a definitive “yes!” I then go upstairs to check on Abby and tell her Kelseys request, to which her eyes light up as she shakes her head vigorously “yeeah!” After that I go back downstairs to find Kelsey playing a card game with my brother and his gf. I walk up to the table and probably not so slyly tell Kelsey, “hey, abbys asking for you for some reason.” She responds with “oh, weird, but okay” with a devilish grin. The round was pretty much over anyway, so Kelsey gets up and walks upstairs. I’m pretty sure my bro and his gf new what was up, and me not waiting even one minute to say “I think I should go check on them” probably didn’t help.