I appreciate your email. Your mom is entitled to her opinions and you’re entitled to your life. I would imagine she’s had a front row seat to all the turmoil you’ve gone through in your marriage as well. This is likely why she is so protective now. The most important thing is not to be asking your mom’s permission as much as having a conversation with her. You want to keep her in the loop and ask for her help, not ask for approval to have your life the way you want it.
The frame for this conversation would be for you to review all the support and care she’s given you. You’ll need to point out specific things about this, and I would explain that you need this kind of help again. This is when you describe to her what’s going on — and what you need. It’s important for you to let her know you are not asking her permission to date who you want. This is your life and you are explaining what you need, not looking for her to give a thumbs up.