Do most men find a threesome appealing?

My husband and I had a very heated conversation last night...it began with us talking about porn. I am not ok with it and don’t know how I ever could be. He said he “doesn’t know if it is bad” and has admitted to using it over and over the past few years. As heartbreaking as this has been for me, that’s not the worst part. Last night, he admitted the idea of a threesome in our marriage is very arousing to him. I feel disgusted and broken. I don’t know who this person is I married any more.

Please, no harsh remarks.