Relationships - When not in that Household

I enjoy playing multiple sims in a general neighborhood, or building (for rent is great for this) but I hate when I go back to a family I just played one season ago, and the partners in the house no longer have a romantic relationship. I'm not playing with neighborhood stories, that needs to much micromanaging for me, just seems to me that if I leave a couple with 100/100 relationship, when I come back to them, it should be in about the same zone. Not 50 or less. On the plus, social bunny is great because I just flirt like crazy through posts and get them back to 100 really quick...but it doesn't seem like I should have to do that.