Love who more?

Clarence keeps getting into trouble with me and boss lately. He has become naughtier, more rebellious and defiant. We are both very upset by his behaviour. Is it part of growing up or is it because of mei mei?
I tried to ask him why is he behaving in such a manner, he told me he felt we love mei mei more than him. Is that the real answer? Oh dear, how can we make him understand we love both of them as much.