On the surface it's the unkindest cut of all ... Arnold Schwarzenegger out bike riding Sunday in Santa Monica, wearing a shirt that says, "I survived Maria" -- the woman whom he betrayed so badly.

But there's more to this story. We found out ... Arnold got the shirt last November, during a farewell party for the Governator's staff. The shirts were actually designed by Maria's staff, as a joke. The shirt they presented to Arnold had 2007 crossed out and 1977 scribbled above -- that's the year Arnold and Maria started dating.

And, we're told, Arnold and Maria are not at war. They're well along in the process of settling their divorce, and they speak frequently.