While I fully agree with what Gunner Ray wrote above, I'd tell my opinion just to try and answer your excellent question:Guys, can I play this game in a way that I get to keep more than 2 slaves without them losing affection?
Lets say I want a harem of lovers while earning money by other means.
Can I keep their affection high without having to constantly switch them to the main slave position and constantly interact with them to maintain that affection?
Thanks!
Yes, you can keep more than 2 'fully' affectionate slaves in the way that both their happiness and affection stays very high in the end of every day.
And with certain prerequisites (and severe restrictions as well, I am afraid) you can do it even without constantly switching them to main slaves and back. Depends on how strictly you define 'constantly', the traits of those slaves and their other personal features, your game-style, how well you have equipped the house and how much you are ready to pamper the girls with eg. TV-nights, repeated visits to Virax Springs and so on.
The more slaves the harder it'll grow to keep them all affectionate, I suppose.
Please notice that I am like Jon Snow (who knew nothing) with this game. Versions differ and the more I play the less certain I get about some features. I am just starting with current 8.1.5b (Public), so I can't say how many slaves I could possibly keep affectionate (and happy) this time. Earlier I had 4...6 affectionate slaves, never more than that, because I am such a lazy entertainer and horrible host in addition.