With constant pool parties? The only ones with affection dropping below loving are the ones specifically with certain traits that forcibly drops affection (Deadly Enemy and Emotionally Detached).
For me, I played since 0.8.2.2 (so maybe you played much earlier), the real stat that I used to see very noticeable drops was Happiness. But the new Household contentment stat introduced in 0.8.3 solves that pretty well. Too well to be honest to the point that traits/items that affect happiness almost never matters once everyone is settled in. Everyone is just Ecstatic levels of happiness every day even with society slowly crumbling around them.
