How has it been built?
Most of the girls have said, more than once, they hate cheating and expect their partner to be faithful.
Unless you skip the dialogue I don't see what you seem to be seeing. Aimie left her fella for cheating, she takes you on a plane where her friend is and offers you a threesome, if you try and go through with it she dumps you she is CLEARLY not interested in a harem and neither are any of the others.
Nearly all of them have stated the exact opposite.
Just because you've been fucking them all doesn't mean it's all going to work out. The signs have been there from the start that fucking everyone won't end well.