Marriages are binary compounds if things go the way they’re supposed to. In binary compounds, the individual elements come together either as ionic compounds, with one element giving up electrons and the other taking, or as molecular compounds, with elements sharing their electrons.
What happens, though, when the oxidation state changes in one of the elements of the marriage compound? The struggle to make it keep that particular oxidation state can rip a marriage apart. Both partners have to be willing to shift, in tandem. This is not always an easy thing.
Somedays, though, things go fairly well and the compound is a stable one.