This was done for a variety of reasons, including their age and temperament, the smaller living quarters in Hawaii, the tropical climate and frequent travels, all with the goal of making our new life as stress-free as possible. I adored those dogs, but I justified their sacrifice to the greater good of a successful relationship.
In other words, "There were a lot of reasons, but my personal convenience trumped them all, and I tried to allay my guilt on the front end by being dishonest with myself so I could work up the nerve to off them."