I think it's okay as long as you're up front about it and try to work through your own issues. I'm pretty sure my ex is bipolar, it runs in his family and even he knew he was exhibiting the same symptoms, but he refused to get help for God knows what reason. Ended up braking up with me three times because he suffered through a lot of issues bipolar people have in a relationship (constant dissatisfaction, extreme mood shifts, etc) and it took him a week to catch feelings for somebody else and brake up with me on one of the most important nights of my year. Worst part is he told me he honestly thinks it'll end in a similar way with his new relationship, and with the way he acts towards me and his friends I honestly believe it.
The point of this is that I believe if he had been upfront at the very least, we would have been able to break up in a way that didn't hurt as much. At the most, maybe he would have gotten the help he needed, and we would still be dating today. Everyone deserves to love and receive love, as long as they are upfront about anything that might negatively affect the other party. Just have to make sure you don't expect too much out of it, the only person who will ever be able to improve you is yourself.