And I completely disagree with what you're saying, and I've also been happily married for a fairly long time. (A long time = 2 Rush Limbaugh divorces.)
"Sexual chemistry" is worthless garbage if your spouse is a nasty, evil, vindictive, amoral person. On the other hand, it's relatively easy to find a kind, loving, thoughtful person tremendously attractive, sexually and every other way.
I'm not sure I follow what you mean there.
If only that were true. If it were, then all the people who are "beautiful on the inside" would be knock-out sexy, adn they aren't. The eye of the beholder thing is in full operation, but if the chemistry isn't there, it's not there. I dated a lot of women who were just duds in the chemistry department. Some of them were the greatest people, but it wasn't there.