I can well sympathise with the MIL problems. My MIL has a real 'superwoman' complex, ALWAYS sniffing around for compliments from her friends, sons and husband. Everyone knows what she is about....to the point that one time FIL spoke candidly with their group of friends that she always needed to be the special one, the fastest one, the one who knew all the gossip etc, in the context of her charging up a mountain trail ahead of their holiday group.....too bad she was within ear shot and she completely froze him out for days......we almost thought the marriage might be over as he dared to speak the 'truth'...that basically she's an insecure ego maniac!
Having watched other MILs in HK, especially when they don't work and are Chinese, I realise this sort of insecurity and need for the 'yay me' activity is very, very common. Yes, she does point out every single thing she does for my daughter, yes, she points out every single thing she does for me (i.e. I bought you soy sauce as your house was out of it.....it was deliberate, I was trying to reduce the salt intake of my family....), yes, she points out everything and it's all about her. Very difficult situation for my DH and also for me. Thankfully I work so have my own income otherwise it would be a whole different ball game.
I try to keep in mind that probably life is not great for her, to feel the way she does and to need validation all the time. Life is probably pretty feral for her in fact especially if she doesn't get her little compliment hits and clearly as she is always angling for them, they are not coming nearly quickly enough, and she probably has an internal dialogue that is probably pretty negative, because, I believe, when one is happy and secure and occupied, you don't need to cut others down to boost your own ego. You just accept......
Cheerfulmama, you need to have a serious talk with your hubby about these trips as it will just wear you down. Don't worry if MIL believes the No s are coming from you, she's probably attributed a lot of negative things to you anyways, and if this is just another run on the board and allows your little nuclear family to remain happy and together...well so be it!
Sorry probably had too much to say on the topic!