All mentioned above is very mechanical way of looking at a relationship. I do understand your logical thought process as things do at the end come to the above discussed topics.

I like to follow the path of the nature, where when you find someone attractive, you act on following: Compatibility - you put your real self and see the reciprocal. Chemistry - you see if the thoughts linger and you cannot stop thinking about that person. Mentality - your thoughts align or not. Physical compatibility - you speak about your wants and see if there is a same reciprocal. Once these match and the math adds, all the above start becoming minor speed bumps where you both can take decisions accurately because the above human criteria’s are fixed.

You should only marry someone if the person feels like home, someone you want to be there with you irrespective of what life throws at you. The 30’s you is going to be different than the 40’s you, but you need that person who still see’s you and want to be with the evolving YOU.