I went through the same thing with my ex fiancé and this is resent but I've forgiven and remaind friends, I don't know I just understand the situation. It's not them it's the illness. I love and care for her but I know I can't do this, I also have feelings and emotions I have to deal with... We still text each other and a phone call here and there just to see how we both doing and I see nothing wrong with it. If you a strong individual and don't take it personal then carry on with the communication because they need all the support they can get, but be open and honest and don't lead them on. I must say she has given me a new outlook on life and for that I'll be always greatfull.
It amazing how so many of us love them so much and they just can't see it.
My boyfriend and have been together almost two years
The same thing happened to me. I dated a man for a year soon after my divorce. I was vulnerable and very trusting. The man I was dating would have episodes, like what you described as bipolar and he hid it from me really well. He was super polite, caring and overall very loving. He'd do really good and then almost 4 months on the dot, he'd have an episode. He'd go from a few days before saying how much he loved me, making plans, hanging photos of us on the walls, talking about moving in, getting married, inviting my dad out to dinners and talking about having babies to a few days later saying he doesn't love me. I was so confused and so manipulated I couldn't tell what was up or down. He'd then beg for forgiveness and I'd take him back. The last two episodes were the worst. He did that when my dog died and I was in so much pain. I loved that dog and then he ghosted. I again forgave him because I thought he was a good person. And then the last episode, he did it again a week later after my brother died. It was disgusting and scary. Went from taking about or future to telling me he doesn't love me. He ghosted on me and 12 hours later one of my girlfriends saw him on a dating website.