My mother in law wants to be involved in everything my boys do. Is it wrong that I want her to back off?

She looks up all their sports schedules on the Internet and shows up. She shows up at my house unannounced. It causes alot of fights between me and my husband. He won't say anything to her but has no problem saying something to me. I really don't like her I say hi and bye bc I don't want her in my business. She looks and reads through my stuff in the house she is very nosey!!! What can I do???