Child custody in a military family often looks different than it does in a civilian divorce. Many young men marry their high school sweethearts before they enlist. Their wives travel with them to wherever they are based. Soon there are small children. The combination of low pay, stressful parenting, and homesickness often destroys the marriage.
Without local roots, and usually without jobs (or jobs worth keeping), military family life for the wives can become a difficiult hardship. Often the wives tend to feel that their best option is to go back home to their families, where they will have a ready made support system for themselves and their babies, including free baby sitters, and perhaps a better opportunity to find a job through family friends. Let's say back home is Alabama.
Typically the initial separation is supposed to be only a temporary visit back home, but it turns into a permanent relocation. This is a dangerous situation for the service member husband and dad when it comes to military child custody, because the California courts will lose jurisdiction over the children to the Alabama courts once mom and the children have been in Alabama more than six months.
In other words, unless dad files for divorce here in California before his children have been gone six months, he's not likely to get them back. Instead, after six months mom will file for divorce back home, and the Alabama court will decide whether the children return to California to be with dad, or whether they stay with mom.
Under those circumstances, it's highly likely that mom will get sole custody of the children, and dad will only get visitation. Because of limited leave time, travel time, and travel expenses, dad will most likely be with his children only a couple of weeks a year while they are little kids.
A military family specificaly "dads", must be aware of this six month rule and file for divorce before their time expires. If they do file here in California within six months, it is highly likely that the California court will order mom to return the kids to dad pending the conclusion of the divorce proceedings. The court cannot order mom to come back with them, but almost invariably she does.
When mom comes back with the kids, the child custody picture changes favorably to dad by a large margin regarding their military family status. The general rule is joint legal and physical custody. A 50/50 time share may not be attainable, but the frequency and duration of the periods when dad has the kids will be far greater than they would have been if mom and the kids had remained in Alabama.