Was I wrong?

My ex boyfriend and I broke up 6 months ago, not on good terms. We’d been together for 10 years, we were high school sweethearts and he never proposed to me or even tried to move towards marriage- he just kept stringing me along so I broke up with him.

He recently started dating a new woman. One important thing to note is that I am a great baker. I love baking for friends and family. One thing my boyfriend repeatedly requested, and that I made frequently for him were my blueberry muffins.

A week ago, his girlfriend reached out to me via Facebook and asked me if I could share my blueberry muffin recipe with her. She said that my ex still raves about the muffins and she wants to surprise him for his birthday that’s coming up.

The recipe is something I developed/created and I really didn’t feel comfortable sharing it with her. I politely told her I would not share my recipe but that I’d be happy to share general baking tips for making muffins. She became extremely upset and started insulting me. I blocked her.

Today, my ex texted me and called me childish and selfish for not sharing my recipe with her. He asked me if I could invite her over to my house so I could show her in person how to make the muffins. He told me it’s the “least I could do” for him and tried to guilt trip me with his upcoming birthday. He also said that she tried to make him blueberry muffins and they tasted horrible and he is getting depressed thinking of never tasting my food again. I blocked him as I felt it was incredibly inappropriate to text me that when he is in a new relationship.

Was I wrong for not sharing my recipe with her?