Understanding the subtleties in commitment and monogamy is a life journey that many choose. Feeling frustration at lack of desire versus deep love and family, is a commonly misinterpreted theme.
There are a few more theories these days to help us understand our monogamous nature and what it really takes for a monogamous relationship to work, and if indeed that is actually possible.
It is coming clearer to the masses now that cheating and infidelity are no longer a must do, that there are indeed options in open relationships. This of course requires commitment also, and indeed a sense of desire itself to exploring this theme. Most importantly it requires communication and the willingness to face up to the challenges as they surface, both as an individual, and as a couple.
This article on monogamy themes has some interesting information, that is likely to get you running hot.