He will stay married to Huma as long as Huma is working as Hillary’s beard.
Huma will stay with Hillary as long as she is considered viable as Presidential candidate. Huma is in the best place right now for her friends & family of the Muslim Brotherhood, for information. If Hillary is elected President, Huma will be their top source.
I can see Huma as WH Chief of Staff in 2017 with Carlos sliding into some gravy DC lobbying/foundation/think tank/etc job.