We're coming up on 38 years, and my wife and I have talked about this. We both agree: there would be no point in either of us remarrying at this age if one of us bought the farm. I've said to friends (half-jokingly) that some time ago, my wife and I concluded that each of us is married to the only person on the planet who will put up with our crap. There's some truth to that with anyone. The older you get, the more baggage you have, and the less likely it is that you'll not only find someone who will put up with it, but that it will be someone who you can tolerate.
I live in a retirement community. This place is full of old men and old women who have recently lost a spouse. I would guess that less than 10% of them are looking to match up with someone new, and many of them are just in their fifties and sixties. Sure, they socialize as couples, but few of them want anything more than that. When you get past a certain age, the foundation of your life is all the habits and beliefs you have grown into over the years, with or without a partner. You're better off just remaining comfortable with who you are than trying to find someone who doesn't want to change you. Someone might come along someday who will make you reconsider, but it's best to live your life as if that is not going to happen.