I gave friend who literally can never see any positive in life ever. To be fair she did suffer postnatal depression and kicked her hubby out a few tears ago but she gas a great job, lively life, lots of weekend breaks etc.
The problem is every single day I get barrages of messages from her moaning, not just a moan but because she doesn't have a partner she seriously offloads .
In Return she is a good friend in that if I ever, god forbid, moan , she die give good straight advice.
I am her only friend left as she had isolated people, she hate people.
I have 4 children, 3 with lifelong medical conditions and one with Tourette's syndrome...yes really! They are all aged between 3 and
11. I work part time and am studying also for a degree. So life isn't perfect.
What I need help with is being a good friend whilst maintaining my sanity! This is dragging me down so much. If I say I find it hard she will say at least you have a husband or your job isn't stressful. This is true, I have a lovely husband who earns a wage but it would give anything did my kids to be healthy.
I do not in any way want to end this friendship, I adore her, have an affinity with her bug because I an not high maintanace I feel the moaning is damaging our relationship 
How does everyone else deal with such friendships?