That’s Not a Thing
There’s no such thing as breaking up with someone because they’re “too good” to you. You can break up with someone because they’re a “nice guy,” but “nice guys” aren’t genuinely nice, and they’ll always give you a hundred reasons why you should back up and run in the opposite direction.
This guy claimed that he treated his ex-girlfriend so well that she didn’t feel challenged. Yeah, because people hate it when they have everything served to them on a silver platter with roses and honey. We don’t know who you are, but we have a feeling that you’re lying.