Have you ever done a threesome?

I’m thinking about doing one with my husband. And I would like to know of people who have done it and how was it? Did it change your relationship afterwards? Did you like it?? I would love to do MMF but hubby only is interested in FFM, which turns me on too, but I’ve never been with a woman and I’m most def straight. I would be ok kissing another girl, but not going down on her. It turns me on the idea of both of us (the other girl and me) going down on him.