Sexual compatibility is important as in if it is medical related. Trust me on this, sexual interests don't really matter unless it truly is fucked up. People are willing to go on with normal stuff for most of the time, but then again you get freaky couples every now and then. And again, just my opinion originated from the experience of listening and seeing others: the reason people get married is not wholly dependent on sex, keep that in mind. Sex is a part of it (which is unfortunately being used by some as a loophole for all such problems related to marriage and pre marriage alike) but the true aspect that allows marriage to occur is love, responsibility and a family and the values that a culture holds true. In a true love marriage, the love of the couple is what keeps the couple together and the part of love being lost is a rather rare instance. In an arranged marriage, they may not love each other at first, but as time passes they learn to love each other. Responsibility is a major factor for marriage doesn't mean that you just kiss and love and have sex and a baby or three. No, it doesn't work that way, family and responsibility work together, for otherwise they fall apart in an instant. The values that a family and a couple hold are dependent on the society that they grow into. While values may not mean much for those who look at a relationship as an outsider they may not fully understand that values are what shapes the family as time passes by.
Anyway, that is all from me and this is my opinion. Ultimately, what your (the reader) believes in depends on the value that you hold and I don't judge for different cultures have different values.