hi and welcome to the forums.
I have a couple of thoughts about this and I look at this from the perspective of husband and child.It is also nice to hear how caring and supportive you are being. At the same time if you are being the person which another person is relying on, you can soak up the negative vibes and sucks you in. So it is also important to be able to find some way for yourself to have some sort of coping tools or life of your own to act as a balance.
I can tell my wife anything, or should. However I tend not to tell her too much of what goes on for the very reason listed below (next section).
Can I ask what sort of help your partner is getting at the moment?
I hope that if I tell you part of my story you might get something from it... i chat periodically with mum about things and life in general. At one of the times in my life when things were worse than today I was chatting about some dreams I was having. I did not get very far into it when mum stopped me from speaking. The reason was that she did not want to worry about me more than she "should" or already does. In that way we worked out a way we could communicate with each other without necessarily having to go into all the details. I also have own psychologist I see, so she gets all the gory details.
It is also helpful for anyone to have about 3 people they can turn to or talk to. So if you are not available for whatever reason, you partner might be able to talk to someone else. It is probably this reason that I do not tell my wife too much as I have some others I can chat with.
Lastly, this should be about you, but wonder what sort of the coping tools your partner has.
I hope to hear from you.