^ I hope it's not the latter.
If so many Starfleet officers (Picard, Riker, Troi, Hunsiker, and apparently Rios) are resigning their commissions because they're angry and disillusioned, that would seem to indicate that Starfleet is in a very sorry state, which I desperately hope is not the case.
In any case, if all that Riker and Troi wanted was to be together, they could do it while still serving on the Titan, amirite? I'm not aware of any Starfleet regs that forbid married couples from serving together.