walked away from a couple because i caught feelings... did i do the right thing

need to put this somewhere honest. solo woman in cape town, mid thirties, ended things last week with a couple i'd been seeing for about eight months. they're wonderful people, properly secure with each other, treated me beautifully. but i started feeling things for the husband that weren't fair to anyone, not to her, not to him, not to me. i ended it cleanly told them roughly the truth (without the full extent of it), they were kind, the wife sent a really gracious message back. now i'm sat alone wondering if i was too quick, if i should have just managed it. how do other solo women navigate the feelings thing... do you have rules for yourself...