Most divorces are caused by differences in the personalities of the two spouses, or by a single action of one spouse, such as infidelity. An artificial womb probably wont have much effect on either of these scenarios. Divorces will probably continues to rise gradually as people gain more social freedoms
No, the artificial womb will not lower the divorce rate, because it will not do anything to help causes of divorce. People get divorced because they think that continuing to be married no longer makes them happy. That has nothing to do with having an artificial womb. People's values are different than they used to be, and are not as committed to marriage.