I believe some people are simply never happy. My mom lost her dog to a car recently. She only had the dog for 3mo, but now she just can't get over it. She has a new one, but wants one just like the old one. So what's wrong with the new dog? Nothing, some people are just never happy/satisfied.
Did our partners "slowly lose respect for us" yes it's most likely. I see that in my sitch. Is it because of something that changed in my behavior, no. She just decided this isn't what she wants. By pursuing, all we do is give them a valid reason to now see us as unattractive and have less respect for us. In fact, they should never have left in the first place. If someone wants to leave you, let them go. Not because it's a game to get them back, but because it's their decision to quit. It has to be their decision to see their mistake and try again.
Proverbs 3:5 Trust in the LORD with all your heart and lean not on your own understanding
