I’ll throw my 2 cents worth in.
In my case I was happily married for 42 years, the last 5 of which involved my nursing my wife through terminal cancer. So what I am looking for is someone to, partially, fill the void left by her passing.

BUT I have other responsibilities; I have 3 children and 8 grandchildren, I do not own much but what I do have is for them. Marriage alters that “next of kin” relationship and that is going to take a lot of thought.

SO, For me I would like a relationship, that may turn into marriage but that becomes something that involves all of my descendants.
I’ve seen the term FWB on a number of these sites so perhaps the best way to describe it is that the F is of primary importance, if the WB part comes along, well that’s good.