I’m male, so no i wouldn’t.
Wether or not you should it’s up to you, as far as my experience (firsthand and secondhand) goes i strongly advise you not to do it unless you’re COMPLETELY open honest and horny towards your BF.
The few experiences i managed to gather about threesomes generally end up in this stereotype: Eithr one of you shows attraction to the third party in a way you haven’t ever shown it to you regular partner. You have no idea how much shit this can potentially stir up.
Secondhand experience: one of my GF’s best friend and her BF had a threesome with said BF’s best friend. (to be clear: two males, one female). She was really attracted to the third party, much moreso than to her BF, which wouldn’t have been a problem if she managed to hide it. I don’t know the details since i’m not THAT nosy but according to her BF she did ON HER OWN to the third party things she not only didn’t do to him even upon request but she also claimed disgusted her.
I know this is shit is crazy, and i mean borderline psychotic crazy, but they’re kinda landmark, their case stirred up epic quantities of shit, i assume, though, that something smaller will stirr up shit in proportion.
So unless there’s NO way EITHER of you can have this kind of reaction (which means you already do, willigly and enjoying it, everything to your partner, and he does the same to you) i’d say DON’T.