I am woman and your question is outside my realm of experience. I feel moved to share here anyway. Please bear with me on this.
What came to mind was an understanding a man once shared with me. He explained that sleeping with a woman is always a unique experience. If life allowed, he would try them all. At the very least, he would want to experience sleeping with a new woman every single day of his life.
And then he made it clear that he loved his wife and that their agreement was monogamy. He explained that monogamy felt entirely against his physical imperative, to continually experience and sleep with new women. He reiterated that he loved his wife and their relationship and therefore, every single day, he consciously choose once again, not to sleep with other women. He explained he had peace with his choice, regardless of how the internal drive still pulled at him every day. He explained that what he was experiencing, in the depth and wholeness of his relationship with his wife, for him, clearly outweighed, the ever tantalizing prospect of sleeping with lots of other women and the variety they offered. He expressed he had no regret for his ongoing choice to be monogamous. He explained that despite his choice to be monogamous, his curiosity about women and the experience of them, would always be present within him.
I appreciated his frankness and the opportunity to understand his experience more deeply. It has always stayed with me.
As a woman, his sharing gave me immense compassion for men and their internal drive for female variety. It seems like I am stating the obvious as I type this. This was not how I experienced men's desire for variety before. It was incredibly liberating for me as a woman to understand. I was aware of how women can often take men's awareness of other women so personally, as if it's a judgement against the woman he's with at the moment. It helped me as a woman to understand, that a man's drive to sleep with other women, is not driven by a choice against any other woman, it is simply a man's biological drive for variety.
How true what he shared is for other men, I don't know. It created an even greater respect in me, for men in relationships, who willing choose monogamy and honor it, as a relationship agreement. I feel tremendous regard for any man's willingness to choose against and sacrifice choosing his biological drive. I now perceive a woman that a man has chosen to be monogamous with, as receiving an honor, way beyond anything I understood before. It's amazing how much we don't understand about one another and unknowingly assume.
OP, I wonder if your current dissatisfaction with your woman's looks, really goes much deeper than just her looks. Perhaps on some level you need to acknowledge or be acknowledged for your daily sacrifice of experiencing the variety of other women in the world. Maybe it would help to consciously acknowledge your sacrifice and the biological pull and all the reasons you choose not to heed it.
I don't know if that makes sense to anyone here or how true it is for other men. I know it feels incredibly odd, to attempt to share a man's experience, with other men, when I am a woman. Now I feel like I am stating the obvious, the sky is blue. I thought I'd offer what he shared with me, in case it resonates or helps somehow.
TL;DR The sky is blue.