I hate to say this, but realistically, he could like something they do better, and frankly, a partner you have may do something you like better. I have no advice on how to deal with it except to point you back to your statement that you're not concerned you're going to lose him.
For what it's worth, I've had fabulous sex partners that I had no particular desire to see again. I've also had partners that were incredibly erotic, whose friendship I've truly cherished, but the bottom line is, no one will hold sway over me more than my husband. The foundation of my marriage is not sex. It's the relationship we've built through the trial of life. Sex is a nifty pastime. Don't confuse it with love.