[mikekchar]

Yeah, a friend of mine had a similar situation, but understood his girlfriend's condition. He stuck with her for a long time (even when she suddenly got married to a different guy). I don't want to speak for him, but despite the incredibly calm way he handled the many difficult situations he was put into, I know it had a pretty big toll on him. Now he's out of the situation completely and I think he is much happier.

With some mental illnesses, you can't really have an effective relationship. The ill person is literally incapable of it, even if they really want to be capable of it. It is not a kindness to try to have such a relationship -- for either party (imagine the hell of guilt the other person must have towards the OP!). I've had good friends who were mentally ill and even that is quite taxing, but you need to know your limits. Again, it does no good at all to offer something to someone when you have no realistic ability to make it work.

I don't think you need to be nasty about it (usually... sometimes it might come down to that). Even if the person has done incredibly bad things, perhaps having sympathy for both parties (yours and theirs) is appropriate. But as the healthy person, you have to be firm and clear about what is possible -- and incredibly often that is nothing.

I really wish there was another way, but you don't dive into the water to save a drowning person, when you don't know how to swim. Instead of 1 person drowning, there will be 2.