For those of you who are in a relationship, how long did you wait to tell your significant other that you have Bipolar Disorder? When is it the right time?

The fact that I am beginning to date again is bringing back all the insecurities. I don't like having to explain that I take many pills per day or have to explain what it really means to have Bipolar. I know that there's no pressure to tell someone right away, but it makes me nervous thinking about the rejection down the road.