How do you deal with a meddling mother-in-law?

It depends on your partner stand. If your partner and you both sing the same song, it would be easier. Otherwise you and your partner will need to come to a mutual agreement. As for me i can say im blessed. Both my husband and i have the same understanding. We clearly draw lines with both of our families. We both agree that at the end of the day, it is out marriage and our family. Both in laws are important too, but who else knows best except for us. It would be good for you and your partner to share the same thing, then can you both handle your family individually. Not sure if i make sense to you. Ill be happy to assist if you have any questions further. Hope this helps.