This is a really bizarre romantic notion.
So your brain is actually divided into 2 brains that are thinking independently and one that you have identified as 'gut' is superior in matters of choosing a partner?
Let me say this.
Go with this thought - after the wedding it will be just a downhill and all the bad things in your partner will become worse.
If you can live with that - cool, go and marry your partner. But if you honestly will think about it and think like "it will be better" or "he/she will change/stay the same" or "after wedding it will be much better" - you are screwed.
You cannot bet your life on "it will be only better". Those things dont work like that, I see way to many people divorcing because they made this bet.
I hate the way to young people marrying out of "it makes sense" while guy goes to strip clubs every weekend and girls dream about some sexy guy taking them for a date. Its sick and sounds like pathology. Its really, really wrong.
Mortgage/Taxes is not the reason to get married. Love is. If you call me romantic, I am sorry, but it seems you didnt really seen true love.
I think reasoning can convince us of anything. The sky is green, grass is blue, etc. People can make themselves believe anything, and sometimes if we get lonely/desperate enough, we rationalize someone's obvious incompatibilities away.