Too big to satisfy?

I love the thought of being with a woman who, due to her size, I can't satisfy. My wife is not getting any smaller, and it's getting to the point where she really looks like she's wondering why she bothers fucking me anymore. Am I approaching the time when I become a cuckold? I can only hope so. Nothing sexier than a woman taking control of her sexual pleasure, especially if her husband only gets to watch. :)