The thing about sexual compatibility is that people who are willing to actively work on that aspect of their relationship often become more sexually compatible with each other than those whom they would be sexually compatible with from day 1. A person who is unwilling to openly discuss their or their partner's sexual needs and desires with their partner is, in my opinion, not comfortable enough with their own sexuality and is therefor not ready to explore kinks of any kind. It does take a certain level of maturity and trust to be able to talk about those things with a partner, so if one person can openly discuss it and the other can't then there's obviously a maturity gap that is much harder to close than the gap in sexual compatibility. Adversely, if both people can openly discuss the topic of sex, with one wanting to explore kinks and the other not having any interest in it, then there is an inherent incompatibility there that they would either need to work around/through or let it destroy the relationship. Let's not also discount the fact that over time, people change. One reason why relationships and marriages fail is because people change and don't work on staying compatible in most (or all) aspects with their partner. Relationships are a constant thing that needs to be worked on.