I just watched these eps with my wife. Her response was “he just tortured him, why’s he want to have breakfast with him? Has he got Stockholm syndrome, or are changelings just weird?” She is pregnant though so she does get angry at odd things.
I always thought that it was just that despite all that had happened, Odo realised that he and Garak had something on common and that misery loves company.
I also have never given any serious thoughts about changings bonking though, so perhaps I am just naive?