Yes, although many people are understanding and tolerant of mental illness. Even if you intend for things to be shorter-term and you say you're not going to marry him, you said you want a boyfriend -- you also said "he is in for a ride". He will pick up on it eventually and then he may leave out of anger because you weren't honest with him and hid the truth. I feel that being honest is always the best policy, but it's your decision.. you seem headstrong on your interest this man.