threesome or no-some

Recently I have been flirting rather a lot with two guys at my gym. They are both very fit and strong, and it is especially interesting since they do not like the one another, and constantly put the other one down.
I see one guy on Monday and the other on Thursday. It is very clear that they are both interested in me as more than a friend but I just can not choose between them.
My fantasy is to invite them both to my place and give them an ultimatum: They both share me at the same time that night or none of them gets me...I think it would be a very passionate threesome as they try to outcompete one another whilst I just enjoy the competition!