Relationships are never perfect and one should never strive for that fake veneer designed for others. For me I've learned that to be in a growing, evolving marriage, I must not be ugly, in action, thought, behaviours, yes also from a physical sense. The turning point for me was to realise our kids made us a family but Sarah and I will never be family, we aren't connected via blood, it's via attraction.
As I've become less of a teenage boy I can articulate what I find attractive but most importantly I had to learn to observe what it is that I do that my partner finds unattractive. That's a really hard thing to do with a fragile male ego. It's a great way to examine ourselves and I hope more male mates take some time to think about it. What makes you unattractive to the people you love? What thoughts, actions, behaviours do you do that you know aren't your best self or good for another human to be on the receiving end of. Once you start to admit them it's hard not to be curious about dissolving them.
For the first 7 or so years of my marriage I was massively ugly in thought and behaviour along with periods of physical ugliness (gobbling up my feelings through food). It's been a conscious journey for nearly a decade that I still make mis-steps in the heat of high emotions, but that is to be human.
I know I am sounding a bit like a broken record but I can't stress enough the importance of mindfulness and meditation practice and it's role in helping me see the shit much clearer. I write this as a breadcrumbs for male mates who are struggling with love and adult life. The way out is through and that starts by going into yourself. There are so many tools, books, videos, psychologists, poems, songs, friends, and courses at your disposal, the only thing for change to stick is you bringing a willingness to change and that means to take responsibility that your old way of thinking (I'm special, it's others, I'm perfect as it, I have no faults, it's her etc) are no longer working for you and need to be dissolved. If you own these as your feelings and behaviours and own them as "killing your relationship", you will be ready for the biggest continual growth spurt of your life.