How to deal with toxic grandmother?

My girlfriend and I have been together for 7 years and recently started a family. Her mother would tell me you always taking my daughter out to nice places, having a good time and I don’t like what going on. Obviously her mother is jealous. Fast forward her mother trying to tell my girl to become a single mother and break up with him. Once I heard that I was so pissed so me and my girlfriend have a serous discussion about this. How can I deal with this grandmother who possibly not gonna change?
How to deal with toxic grandmother?
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