He meant in Guard regiments. It will probably be taboo in some, especially tough discipline ones like Mordians, while impossible in all male or all female ones like Vostroyan ones or old Valhallan ones.
As for the RP, I guess I go back to my old job except now as a war veteran?
I know exactly what he meant, and I see nowhere that sex is taboo at all, nor any particular 'type' of sex, for that matter; I'm not saying everyone are nymphomaniacs, but nowhere is it written that day-to-day activities such as that are prohibited.
What exactly is his old job?
I imagine he and his fellows would be mixed in with the Guard units, technically being serving troops and certainly faithful enough for it.
Also, before you type anything, being linked to the Ecclesiarchy means nothing when the need for troops is great and your character had meaningful battlefield experience.
Candy Cane Elf,
Holr,
AdvancedJ3lly