Evie, Jacob and Henry are all in a consensual, happy threesome relationship, they are all ever others lover, deeply in love with each other and no one holds more 'status' than anyone else. They all live happily together, share a bed etc and maybe even have children together.

How 'open' they are about this is up to anon, but I kind of like the idea of rumours - mainly by the Templars, that can never be proved and the the Fryes and Henry remain at the top of high society. Extra bonus if they all somehow married each other, so they can be each other's husband/wife at different times and at different functions.