Michaels, 35, who has two children with the singer, took to her blog Saturday to express her shock and dismay over Etheridge's filing.
In a post titled "blindsiding," Michaels writes, "gentle waves / no noise for awhile / or maybe gentle voices and / SMACK!!!!!!!!!!!! / FILE FOR DIVORCE!!!!!! / even though we both promised / agreed / handshook / pinkyswore / no filing until after the tour / in the fall."
But it seems her qualms about the end of the relationship extend beyond just the timing.
"Her broken promises / told to me by/headlines / i'm raising the kids / doing what i can / second set of yours," Michaels writes.
In Etheridge's filing, she cited irreconcilable differences as the reason for the split and asked that the court not award Michaels financial support. Michaels gave birth to the couple's son Miller and daughter Johnnie in 2006.
"Could you stop blind sighting [sic] me?" she concludes. "Unless it's another art form you're working on / have a good concert."
A rep for Etheridge couldn't be reached for comment.