Many couples looking for fun; Threesome is a good idea in a relationship?

I'm talking with many couples in this time of my life, and some guys and girls want to live a new experience sharing your partner with me, I confess that I'm a bit scared about that indeed I was married for all my life and I never thought   share my man, but now in this time of my life I'm liking this  idea,I already have had decided that I will do it, and who will be my new partners for fun.
That's amazing, when you have a good relationship and you agree share your partner with another person and the both have fun together, for me it's the maximum of love and trust that someone can demonstrate to your partner.. Congratulation couples you guys are wonderful people.