Trace Adkins' life has been TOUGH -- He's been shot by an ex, his home BURNED down about a year ago, he was hurt when a farm tractor rolled over on him, that drunken fight with an impersonator , rehab, the death of his father and now a divorce..which according to TMZ has been in the works for over a year!

Trace's wife, Rhonda, filed divorce papers this week to end their 17-year marriage ... but Trace says they're still united in a way more important way -- making sure their children come first. The kids are 16, 12 and 9.

We're told Rhonda's decision to divorce was a long time coming -- and both say they're torn up by it.

Please keep this amazing friend, former B93 Birthday Bash Headliner..and all around great man!  I consider myself lucky to call him a friend.  -Conrad