sj I am so sorry! I am concerned that you feel like crying all the time. That is a horrible way to feel. This is obviously a worse problem than it sounds, since, like Old Meg, I thought if they don't visit that's a good thing! But clearly for you to feel so unhappy there is more going on. Is it possible to talk about it with your Partner? What about his DDs' mother? Is she able to take some of the burden or would she make it worse?
I want to say 'let them get on with it' but I suspect this is too flippant because you wouldn't be writing if that were possible. I think talking to your P might help. I also think if you are crying of feeling near tears a lot, it is worth seeing your GP and talking it over. It's so hard to cope with anything, let alone difficult people when you are depressed.
We do have an expectation that these are Golden years, but no one tells us about difficult adult children, so don't get upset about your life because it is quite normal in that respect. I mean, to have problems with our offspring when we are retired is not unusual, it happens a lot. I think our generation is less inclined to protect ourselves and put ourselves first compared with the younger generation. Maybe your P could start saying not this time to the money requests? Unless it is an emergency. Maybe the children have become spoilt and he is a bit scared of losing them? He is in a divorce situation regarding his daughters, I assume? It might be very hard for him, he could feel a bit scared of them. But he needs to attend to you and I think it would be good if you gently got him to see you are feeling so sad about this situation that it is affecting you all the time. Ask him for some loving support and help. I know it's not an English man's gift (if he's English) but he might be glad you trust him enough to ask.
I do hope something will change to alter the dynamics and things will get brighter soon. Please tell us how you get on. Lots of love, L 