[LS] Played Sims satisfaction changing when not active household

I wanted to add something I've noticed with Romantic Satisfaction decay.  I have experienced the decay when rotating households and also a rapid decay in active households or couples.  However, I noticed in my current save that there was no romantic decay in my sim's romantic relationships UNLESS they were official (i.e romantic partners, engaged, married). 

My young adult sim is trying to find 'the one' and has had romantic interest in a few sims.  I've noticed that if the friendship and romance bars are full but she is NOT in any kind of OFFICIAL partnership, the romance bar did not decay at all over a couple of sim weeks, despite several sim days passing without any romantic interaction between them.  However, as soon as she became a romantic partner with another sim the romance bar started decaying the very next sim day.

I've no idea if this observation helps or not but I thought I'd mention it!  So far I've only noticed this in the save I'm playing in at the moment, I haven't tested on any others.  This save also used to be modded, but I removed all mods and CC from my game a few months ago and have been playing mod free since then.