My mother and I have had a very difficult relationship for probably the last ten years or so. There is a huge backstory so will summarise to avoid drip feeding.
Periodically, she will stop talking to me for some insignificant reason and she will never really explain why or what I did. I generally ignore her when she has these sulks and at some point she will resume normal relations as if nothing happened. Usually this will be when either she needs something or because she's not talking to my sister (they have a similar relationship) so she wants to have contact with me again instead.
She also has a tendency to blow hot and cold with other family members and has strained relationships with all my uncles and aunts (her siblings and their spouses) and my grandmother (her mother) who she refuses to talk to at all. We also have a huge extended family and again about half of them either she won't talk to for reasons that are usually unclear or if she does tell us, reasons that are minor. Other family members have ceased to have relationships with her because of her unpredictable behaviour and nasty things she has said to them in the past.
DH and her do not get on at all. This is mainly because when we got engaged, she immediately decided that she wanted nothing to do with the wedding (again reasons never to be revealed) which upset me greatly to begin with. Of course, we just decided to get on with it and started planning our wedding with my dad and without her. At this point she decided to become a nightmare mother-of-the-bride-zilla and started planning a crazy big wedding that neither DH nor I wanted. She went as far as booking things and paying deposits without asking us. When we found out angry words were exchanged, both she and DH said things they shouldn't have. DH apologised (no apology from her) and we tried suggesting compromises but she refused them all. In the end we had to carry on without her again and she spent most of our engagement sending nasty emails to DH and making angry phone calls to me. At the 11th hour, family friends intervened and managed to convince her to come to the table. After this wedding plans were made in line with the original compromises that DH and I first suggested and we did in fact have a wonderful wedding day. However, after all the stress and heartache it took to get there, coupled with the fact that she refuses to acknowledge that she ever did anything wrong, although DH and I try to have a "normal" relationship with her, I don't think either of us will ever really forgive her. She is also still very angry with us because as far as she sees it, we excluded her from our wedding preparations and were rude to her. Also, in her eyes, we would have had a much better wedding if she had been allowed to organise it all as per her wishes. She brings this up regularly and we ignore, but we are never allowed to mention her behaviour during this period else she goes into full tantrum mode.
So backstory over, now with the current situation. DH and I have moved abroad. She has decided to visit for five weeks over Xmas and New Year. When she first suggested it, I tried to put her off by pointing out that during the week we are both at work and are out of the house for at least 12 hours a day and that there is very little to do in the city where we live. I thought it would be sensible if she broke up her stay with other activities. She said that she would book a holiday to see a bit of the country we live in. Also we have other relatives a two hour flight away so thought she could go and see them for a couple of days, which she seemed keen on. However, she has booked neither, nor any of the other trips that we have suggested. Instead, she has spent all her time cleaning our flat because it was dirty (we have a maid that comes for a couple of hours every day but this is clearly not enough) and rearranging our kitchen because she couldn't find anything 
. She has also cooked a lot of food and continues to cook more even though we now have a fridge full of left overs and no more space in the freezer and keep telling her to stop. She is also buying a lot of "stuff" for the flat that we do not need eg extra saucepans when we already had a full set (apparently ours where not very good). I've made a point of not saying anything to avoid any arguments but things came to a head yesterday when DH found her opening fresh packets of food and emptying them into jars. Not generally a big deal but as expats we have brought lots of food with us that we don't easily get here so there are shelves and shelves of foodstuffs to empty out. DH asked her to stop because (a) anything we don't use we can't take back so easier to give it away if it's in its original packaging and (b) we live in a hot country were things go off and there are lots of pests so better to keep foods in sealed packaging. She took huge offense and decided that she was moving into a hotel because DH was rude to her (I heard the conversation and he was not). Angry words were exchanged on both sides and DH said stuff he shouldn't in the heat of the moment but immediately apologised. As far as my mum is concerned all this is our fault. DH was at fault for being rude and although the apology was clear and immediate it doesn't count supposedly. Also neither of us is sufficiently grateful for all the cooking and cleaning she had done. Obviously she is not to blame at all even though she spent most of the day either sulking or ranting at us about variously the current situation, the whole wedding drama which was now nearly five years ago and which she cannot accept any blame for at all, or other random things that other people have done to her (ie things that are nothing to do with us at all but worth bringing up in an argument to point out how hard done by she is).
After all yesterday's drama, DH managed to convince her not to move to a hotel by telling her that I was pregnant so she should think carefully if she really wanted to break off all relationships with us and therefore her GC. I'm only just 12 weeks gone and we weren't planning on telling anyone for another week or two but felt forced to under the circumstances. She decided to stay but spent the rest of the day sulking and still isn't speaking to us.
So, if anyone is still reading after that marathon story, what are we meant to do now with her hanging round our flat continuing to sulk. She is due to stay for another three weeks and even when we were on speaking terms she refused to tell us if she had any concrete holiday plans or when she intended to go.
And also what do we do when the baby is born? She has a habit of conveniently forgetting about previous arguments when she wants something and will no doubt want to come and see the baby and "help out" at the same time. I don't want her help, mainly because it comes with too many strings attached, and I don't think she can stay more than a week as it's too much stress but I suspect that she will want to plan a visit for at least a month and will again be vague about her plans so that we can't raise any objections. Also, DH's parent are both lovely and I'm happy for them to come for as long as they want (although I don't think they will come for more than a couple of weeks) so she will notice the difference and object if we say she can only stay a week. I just don't know how to have a rational conversation with her and convince her not to plan an extended stay without all hell breaking loose.
In the longer term, I'm not sure how much I can/should expose a child to someone whose affections can be withdrawn so easily. So far she has made an exception for the children in the family and doesn't directly say anything nasty to them. However, she has no issue with having hideous rows with parents in front of any adult "children" who may be present so I am concerned that she will have these sulks and tantrums with DH and I in front of our children.
To be honest it all feels like a bit of a mess and I don't know if I can handle her or if I should even bother. But then I don't know if I can deal with the fall out of telling her that enough is enough and I'd rather she left me, DH and our DC alone.