Well, if you ask a question; you're going to get answers.
And they won't always be answers you'll like.
Furthermore, you know nothing about me nor about my sex life. As it happens, I have had threesomes in the past (though with me and two men, not another woman) and they were the most boring and unfulfilling experiences of my life.
Many years later, I am in a satisfying relationship of more than 10 years - with the same man, and only that man - and we don't need any extras to spice up our lovemaking.
My BF says I am still as beautiful now as the day he first saw me - and that I turn him on no matter what I'm wearing or what I'm doing. If that's not enough to make me nuts about him, I don't know what is.
Honey, don't use the excuse that you want to "spice up" your sex life to explore a hidden facet of your personality.
If you've always wondered if you may be lesbian or bisexual, then just get a divorce and then, once you're single, have sex with anything that moves.
You'll have as much "spice" as you can handle and your husband can go on and find a woman who will love and treasure him - and just him.
Everybody wins.