The 46-year-old singer admits her split from Kendu Isaacs has been "ugly, public and nasty".
Speaking during a panel, she said: "I don't know if people seen the last eight or five years of my life, but its been hell. And its been ugly and its been public and its been nasty.
"So, in the midst of all that. And the stuff that people don't even know about - fighting for my life, fighting for my marriage, fighting for my morals and everything - I discovered my strength. My strength, my real strength is discovered."
Meanwhile, the 'Be Without You' hitmaker previously admitted she "no choice" but to divorce her husband.
In a preview of her new documentary 'The Making Of: Strength Of A Woman', she said: "I'm in the process of helping myself. It's not something that I wanted to do [getting divorced], but I had no choice. I'm not writing an album preaching to anyone about what they should do. I'm literally trying to heal myself through writing, through singing, through some kind of way of getting it out of my system.
"I had to do something other than what I would normally do. I had to get out of my environment, out of my comfort zone, take a long hard look at myself in order to embrace everything that was happening so I can love myself out of the whole thing and that's how this album was originated."
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Mary had admitted in the past that she felt alone in her relationship with her estranged husband.
She said: "I can sense that I'm not what you want anymore. You start to realise that this man doesn't want you and he's just gone all the time and you're by yourself in the relationship. When you realise you're by yourself and you're just suffering through it, now it's time to do some investigating. When I got the full proof, I didn't have to investigate it. It just showed up."