I had a successful relationship that ended, for among other reasons, because of a huge downswing into depression. All my dates and short relationships were started while "up" and that was definitely a reason for why they happened. I was undiagnosed and always just assumed it was SAD or depression.

Recently I just started dating a woman, who has her own stuff going on but under control, who was surprisingly very receptive and okay with what's going on. I think it has more to do with finding the right person that regardless of what's going on, you match up with and then hoping they're accepting too. I think it's nice to think that way just because it feels a tad more hopeful.