Avril Lavigne & Chad Kroeger -- Calling It Quits After 2 Years Of Marriage

Avril Lavigne and Chad Kroeger just killed any chances they had at becoming Canada's favorite celeb couple -- they're separating after being married for two years.

Lavigne posted a wedding day pic and said, "It is with a heavy heart that Chad and I announce our separation today ... we are still, and forever will be, the best of friends."

Even though she didn't use the big 'D' word, that statement makes it pretty clear ... the marriage is over. This was Lavigne's second marriage and Chad's first.

This is now officially the 2nd worst thing to happen to Kroger. Nickelback ... anyone?