I dont think they forget very easily... Missy remembered her breeder and mother and siblings, she was seperated from them at 8weeks when we took her home, and was reunited with them about 6 months later and went up to all of them like they were family.. I really think she knew them...
And my ex-boyfriend and bought a golden retriever together in 94', we broke up in 98' and he kept her... I saw her in Jan and once she heard my voice she was all over me, she knew I was her long lost Mama
Maybe Sammi was mad at your ex-husband or sensed the tension?