Wow. Your male cat is so sweet. One reason behind this is that it was the first pet that came and at then it was only u who accompanied hit. But later when the female cat came, it had you as well as male partner. So it is showing different attitude. Another reason behind its odd behavior, hiding from in dark lonely places, indicates that most probably your cat has conceived young ones. It is a sign of pregnancy so you should not worry about it. If it is pregnant then let it do what it is doing. In case it is not pregnant then give it more time and attention to make it more comfortable. Does your male cat get aggressive when the female cat is around you? It can also be one of the reasons.
