I can see both sides of the issue.

I cut my friends loose when this depression started. I don't want to bring them down. And I have no idea how my husband stands it with me.

My husband is here for me, regardless. I can't help thinking how nice it would be to have real life friends to call on.
Maybe, like me, she's a different person. Maybe all you need to do to be a great friend is to let her know that you're there to listen.

Unless she's a strain on your own mental health. Then it's your own call what to do.