Can I legally marry despite family threats and mental harassment?

I am a 30-year-old man working in a private firm as a sales professional. I have fallen in love with a girl of the same religion (Hindu), whom I met on a matrimonial site. She is a divorcee, and while her parents have no objection to our relationship, my single mother is strongly against it. Despite our efforts to convince her, she is emotionally blackmailing and abusing both of us. She has even threatened to disown me and hurt herself or us. She is causing extreme mental harassment. Please help me with legal and practical guidance.