My current partner suffers from depression. When it affects him things are tough and I find it hard to know how to help him with it.
But he is a wonderful, good and decent man. He has NEVER made me feel responsible for his mental health, not once. He has never made feel like I must stay with him or else something awful will happen. He doesn't try to make me feel sorry for him. In fact when it's affecting him he tries to hide it from the rest if the family as he's worried about the effect it might have on us (he shouldn't but that's a different story).
Also there is a sense of it being an illness, in that it's not with him all the time, and that it's something he wants to fight to get better, easier said than done when suffering from it but still there is an underlying knowledge that it is something he could be free from.
DP has never got so low he's attempted suicide thank goodness. The people I do know who have attempted suicide however did it quietly, without first telling anybody or making anyone feel they must act to stop them. Those who are still alive are by chance, one because of a stranger stumbling across them, and another because a close friend had a gut feeling something was not quite right. Both entered the mental health system after as they were very ill. It is thankfully now a part of their lives they have been able to put behind them. A dear friend of DP's was sucessful in his attempt sadly. No one knew what he was about to do, he just did it.
With my manipulative ex on the other hand, he would threaten suicide, and make me feel I was responsible for keeping him alive by being with him. He talked about it much more than doing anything about it. He did eventially make a few suicide "attempts" but i can see clearky now they were (largely sucessful) attempts to manipulate me, not to end his life.
Also, outside of when my arsehole ex was having an "episode" there was no sense of him being ill, or of it being something he needed to fight to get well again. It was just something he pulled out of the bag every now and then.
He also dragged other people into the whole drama. Once for example after I tried to leave him, he got really drunk and told a friend of mine he had overdosed on loads of painkillers.
She called me, I called the ambulance and she sat with him till I came.
I stayed with him and dealt with the police (they always attend suicide 999s I think) and went with him to the hospital and stayed there all night with him. They had him on a drip. In the morning they got the results of a blood test back. Nothing in his blood. He lied about how many pills he took. Even then I didn't see how clearly it had been done to manipulate me.
How fucking selfish of him to waste everyone's time care and precious resources. The thing that makese angriest though is that my friend he was with lost a close family member to suicide He knew that and yet still put her through that in an attempt to manipulate me. How low can a person be?
Of course none of us know the OP's BF and there is a chance he really is suffering from depression. But from what she's said, it sounds an awful lot more like manipulation than depression.