Situation 805: “My girlfriend’s mom doesn’t want her to get remarried”

My Girlfriend lost her husband in 2017. We’d all been friends for years. We began dating not long after he passed away. It started as me spending time with her making sure she was OK and accompanying her places. We went to the Flower festival together that year and that’s when I knew she was the one for me. I told her how I felt not long afterwards and we began dating. It’s now been over 3 years. I have a ring for her and We’ve discussed getting married. Only issue is her mom doesn’t want her to ever get remarried and her mom has a hard time accepting us being together. I consider her mom my mother in law. I respect her position in my girlfriend’s life. I respect her authority. Do I absolutely have to get her mother’s blessing before I officially propose? My girlfriend has said she’d accept a ring from me. Help me out here.