Mine vary depending on my mood and...well, frankly arousal, if we're being perfectly honest. Most of mine are pretty tame. Most.

Consistently though, I notice that whomever I'm fictionalizing as my partner is a spouse, really only ever changing from that role if it falls outside of my "mostly tame" stipulation. The person changes, but rarely if ever the role. I know personally that I want to share the emotional bond and the love with a person more than I do the mere motions of the act of sex, so I suppose that's my subconscious reflecting that desire? I dunno. Freud isn't exactly on hand to interpret that one for me.