I don't think Starfleet has such a 'lower rank' protocol - or if they did then Picard seemed to violate it quite nonchalontly in 'Lessons' when he had his relationship with Lt Cmdr Nella Darren.
And Janeway wasn't married - unless you mean 'to the ship' style.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist