One day after the singer went on a long Twitter rant where he claimed he couldn't remember marrying Moore, an insider revealed Adams' attitude during that time made their time together "impossible."
"Ryan could be terrible to Mandy when they were married," the source told PEOPLE. "Yes, there were good times, but he had so many issues. He constantly belittled her. And he was selfish and made everything about him," the sourced added. "[Mandy] tried so hard to be a good wife and good friend, but he made it impossible."
The couple married in 2009 and announced their split six years later.
"She didn't deserve it," the insider added, before saying that Moore, who's now engaged to Taylor Goldsmith, has moved on.
"Everything happened the way it was supposed to and she is truly happy now. Taylor is the perfect fit for her and she doesn't even dwell on her past with Ryan. She's happily moved on," the source shared.
Adams' Twitter comments came after Moore opened up about her divorce in a recent interview with Glamour, calling it a "very unhealthy situation."
She admitted that she felt "spiritually and fundamentally stuck" before she split with Adams. Once it was finally over, however, she felt as she had been given a new life.
"I don't feel guilty for it," she said. "I don't fault myself for it. When people said, 'I'm sorry,' I was like, 'No. Sorry would have been had I stayed in a very unhealthy situation.' I didn't. I found my way out. And when I did, things opened back up again."
In his tweets, Adams claims he was so high when he married Moore he can't remember saying "I Do."
"Doomed from the start... If only I could remember the start," he said in his message.
"When someone told me we got married I thought they were joking," he said. "Then I realized how many painkillers I was taking. Honestly there weren't enough to numb the shock. Gollygoops."1comments
"Sometimes you get stuck to the spiritual equivalent of a soggy piece of cardboard. But it rains on net-a-porter everyday when you're trapped inside yourself," he continued. "Take the money I'll take my pride, any day."
Moore and Adams announced their split in January 2015. Moore is expected to tie the knot with Goldsmith in late 2018.