It's really hard to disagree. If you substitute "comitted relationship" for "marriage", then it should become obvious that in the relationship, both (or all, I don't hold to the enforced idea that comitted relationships can be between only two people) people should be able to have their needs fulfilled. This applies to any aspect, not just sexual aspects of the relationship. It is also a fact that in the vast majority of cases, people don't compartmentalize the aspects of their relationships. If something is wrong with one part, then that does affect their outlook and behavior. So, they tend to react to that by looking at other aspects of their relationships, and then making decisions on those actions/reactions.

IOW, if one partner is dissatisfied with his/her sex life, the usual reaction is to either nag their partner(s) to change in ways acceptable to the dissatisfied, or to retaliate in some way.

Healthy give and take also comes into play, but unfortunately, not a whole lot of people tend to do this.

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