I am wondering if anyone can offer advice on how to feel comfortable in creating the sexy romantic character of dances like the rumba with a partner that is not your spouse?

Meesha. 60 percent of Rumba is acting.
A few years ago in a lecture a former world champion who won again later with another partner said that she was taking acting lessons as well as jazz ballet lessons to improve her performance on the floor. Her actual words were. I want to be able to stand in one spot for several bars of Rumba and not feel like an idiot.
Just incase you dont know. Every expression, every tilt of the head has been choreographed and rehearsed over and over again. And then some more.