Let's say that you meet a beautiful women, you guys date, but when it comes to sex, it's either terrible, boring, or she just lays there like a dead fish or gets angry and tells you to hurry up and cum. - what would you do?
Sometimes marriages are just not about sex.. People have evolved to be liberal these days. Wise people save marriages and be open about things and help each other whenever/however required
I think the first thing to do is test each other's communication skills. If you're serious about one another that's going to have to be more important.
IRL...some people are just not sexually compatible, and trust me.... it doesn't (naturally) get better with time. So don't be afraid to bring up what will undoubtedly be one of the most difficult conversations of your life (so far....LOL). In the end, people only change if they want to....and education is the key (there has been a plethora of information about sex and sexual pleasure, and sexual dysfunction published).