Age means nothing. My husband is 20 years older than me...so what? He’s the love of my life. We met when I was 35 and he was 55. He just turned 70 and I turn 50 next month.
Two points:
I don't know what your circumstances are, but Bruce Willis is fantastically rich. It's hard to imagine that the models are unaffected by the prospect of all that money. In fact, it's unlikely that either party was attracted to the spiritual strength, deep convictions, moral courage, honor, integrity, loyalty, or other virtues of the other. So I suggest that it's quite unlikely that marriage is going to stand for fifteen years as yours has.
Besides, the age gap is much greater between Bruce and his new wife than between you and your husband.