If you are mentally ill and your partner doesn't believe in mentall illness so you are not telling him about it, the prognosis for your relationship is not very good. In order to have a successful relationship, you really need to be able to open up to and trust your partner. Perhaps if you slowly explained the situation to him or brought him with you to a therapy session, you could get him to entertain the possibility that mentall illness is real and you are suffering. If he calls people with mentall illness "crazy" and you don't feel like you can talk to him or get support from him, why do you want to be with him? If you are ever going to have a real relationship, it seems that you need honesty and communication.