"We were together for 10 years, married for four, were very quickly divorced, and are friends. I'm still processing everything and figuring out where to go and what happened," Lambert reveals in the January issue of Cosmopolitan, on newsstands Dec. 9.
"[Marriage is] a tough business, and we gave it our best college try … I had a great relationship with an amazing man, so I know what good is. I have a great launching pad for the future. I will never take that for granted."
Lambert, 32, says she is not yet ready to date again. "If I ever were to get married again – which is completely not on my radar at all right now – I feel like it's not about it being a step in life. It's not about a piece of paper or a diamond. It's the way you feel about somebody and the commitment in your heart."
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The "Little Red Wagon" star also talked about her next steps in moving on, saying: "I just want to live a life full of everything. Some of that might mean nights on my porch crying, drinking whiskey, and going, 'Man this sucks right now.' I don't necessarily want to know that I have really bad, long, lonely nights ahead of me, but I have had some, and I still have a bunch ahead of me."
She adds, "It's about living in the moment and feeling every tinge of pain, then waking up the next day and going, 'All right, I'm going to ride my ponies. I'm going to have a girls' night.' That's where I am. That's where I'm gonna live...'"
Lambert has been channeling that hurt into her music, and tells the magazine that she's focusing on her career more now than ever before.
"I just love what I do so much. I love songwriting and the road and the family of country music," she explains. "I love being a female in country music and lifting up other females of country. I'm more in it right now than I ever have been."
For his part, Shelton has since begun a new romance with Gwen Stefani.
Last week, Lambert – who celebrated her birthday earlier this month – headed home for the holidays to spend time and roadtrip with her family.
"Nothing beats a handwritten note from Mom. #homesweethome #cheetosandwine," the country star captioned her Instagram snap.