You've said it all. My dear, as long as you're not a legally practicing relationship therapist or marraige counselor, the possibility of getting into trouble when you try to settle disputes among couples is very high that is why like you, I try to always mind my business.
Only that sometimes you may be implicated if they fight and kill each other so it's best to try and intervene.
My friend had a misunderstanding with her friend one time. We were all schoolmates but I and my friend were a senior to the girl in question while in school. We're equally older than her in age too. It's not the first time they quarrelled so my friend said she was done, that would be the last.
I adviced her to keep her distance from the girl since the embarrassment and insults were reoccurring. My friend asked me for my advice o.
Few weeks later, they were back together and they started calling each other besties. I felt like the devil who tried to separate them and since then, whenever they fight I just pretend I'm not there. That's because they'll likely reconcile and will discuss my advice with each other and make me look like I'm evil.
Anything that concerns settling of dispute, I don wash my hand commot.
I learnt from your post though, atleast you tried your best to help the situation of those couples. Well-done.