A little background:
We just moved back to my hometown - it was a pretty fast transition and dh started his job last Monday and we're staying with my parents until we find a house of our own.
Anyway, mom and dad always take dd on their walk with the dog after they get home from work. They stopped at the park so dd (27months) could play on the slide for a bit and when it was time to leave, she didn't want to, so mom said to her that if she didn't come along they couldn't come back the next day. This is fine, it's logical consequences and I use the same technique (I don't like to physically force her along). So mom was telling me about it and I commented that it does seem to work with her. Then mom said "Pretty soon you'll be saying 'If God wanted you to be in charge, he'd have put you here first'". Well, she's brought this up before and I haven't said anything, and maybe I should have just let it go but I was sick of hearing it, so I said "I don't think so . . . it still gets my back up" - anyway, after that she didn't talk to me the rest of the night.
The next day dd was tired and started throwing a tantrum and mom started telling me (again) that I should just tell her to stop it, that she shouldn't "hold the rest of the house hostage" when she gets upset and that "you don't see me throwing a tantrum and taking it out on everyone when things don't go my way" (to which I almost wish I would have said "uh . . . yeah, you do") blah blah blah. Anyway, I said that I would prefer to teach her how to express her emotions in other ways rather than just stifling them. To which she replied "Well, we must have been the worst parents in the world". I said "Are you kidding? You were great parents, you've given me great things to build on" or something to that effect "Does it really bother you that much that I'm going to do a couple things differently?" Anyway, what I wish I could have gotten into was how I don't want dd to feel like she can't come to me when she's upset, I don't want to be a "fair weather mother", I don't want her to feel that I wouldn't understand her suicidal tendencies as a preteen or her ppd after having 2 babies to the point that she doesn't even bother to tell me . . . I know these things would have done nothing other than make mom angry, so I said nothing.
Thanks for letting me vent.
My mother lives with US. I will tell you right now that you HAVE to start talking when emotions are not running high. I tried to write more, but it wasn't coming out right. We love having my mother live with us, so I know it can work.
My mom also gets offended when she see me do something differently than she did (and my mom was very AP) and tells me she did the best she could. I always tell her that I think she did a great job, but I'm finding my own way as I go along, just like she did and I appreciate that she's letting me find "my best way." For some reason, this makes her feel better.
I also agree with talking to her when it's not the "heat of the moment" - but instead of tell her the things she did wrong, maybe you could approach the subject of overall parenting and that there are some things that are very important to you and dh - explain what they are and explain that when you are in the process of disciplining your dd, you'd prefer she not "step on your toes".
It is always hard to share space. Because its her house, she does have the right to make rules that impact her or her house -- the "no juice in the living room" sort. She doesn't, however, have the right to tell you how to enforce them. And guilt-tripping is never the right way to make anyone pay attention to your needs! I'm not sure where "no temper tantrums" falls in that though. After a lot of reflection, and with some reservations, I think she probably does have the right to say that tantrums must not impact her. So maybe you will need to take your daughter to your room or something when they start. Beyond that sort of thing though, you have to give her "boundaries". You are going to have to figure out how to say "this is my decision" and stick to it. With my mother, that would look something like "I appreciate that you did the best you could and now I'm trying to do the same. I appreciate your sharing your opinion but DH and I have decided to do X." After that, find a 1 sentence reminder and just keep saying it over and over. And good luck!