According to court documents obtained by ET, which were filed Wednesday with the California Superior Court of Los Angeles, the 59-year-old actor cited irreconcilable differences as the ground for the split.
Arnold is also seeking joint legal and physical custody of the couple's two children -- 5-year-old son, Jax, and 3-year-old daughter, Quinn.
As to the division of their community assets, the documents state that the court will determine how to divvy up their respective physical property and monetary assets at the time of their divorce trial.
"For the last couple years we grew apart and have been moving in different directions, which is why at this time we have decided to end our marriage," Arnold said. "I told Ashley that it's her life, we had great years together and there doesn't have to be a reason or a bad guy to move on. Go live your life, you owe me nothing."
Regarding the couple's children, Arnold said in his statement at the time, "We’re both crazy about these kids. We have two amazing children that we love very much and while she has moved out we will be working together to co-parent.
"My kids are my entire life and their happiness is all I care about," he added. "We ask for privacy during this time of transition in our family.”