It's common for one spouse to move some distance away after a divorce. They may be seeking someplace with a lower cost of living than pricey Southern California. They may want to live near parents, siblings or other family members. Perhaps they opt to take a job that pays better or offers more opportunity for advancement.
When there are children involved, if the move is out of California, you'll typically need to get your co-parent's approval or the court's. If the decision to move is approved, co-parents should develop an interstate parenting plan to help ensure that the children are able to maintain a relationship with both parents. That's the case whether they're moving with one parent or remaining here with the parent with primary custody while their other parent moves away.