Before meeting Master, I was the o/l sub with someone who had a r/t long term sub. For him at least, although I didn't realise this at the time- I was a diversion, a sort of fantasy sub, with whom he didn't have to deal with his r/l issues. I think the very fact there was little likelihood of us meeting made it more interesting for him.

I don't know how it is for other Dominants who have o/l and r/l subs, but that is certainly how it was for him.