The first time my husband filed for divorce he had it sent in the mail. This made it easier and was less costly (although he didn't tell me about it and I did think that was really chicken$hit of him... so yes, it's probably best to let them know). The second time he told me he'd have it sent to me in the mail, kept putting it off, but then got angry at me about something and had it served immediately the next day. That was an ugly sitch, hopefully yours won't go that way.
In the meantime I hope you're preparing for the financial and legal aspects of divorce. Before you tell him or file I suggest you get your ducks completely lined up. Read some books about divorce and get to know your legal rights. Be sure you document any information (i.e. dates and details) about missed custody time, negative occurances with OW, etc... Although California doesn't recognize infidelity as a crime, most judges tend to look pretty negatively at shoddy parenting. That may help insure you get more custody.
By the way, if you're planning to change the LS to divorce in 6 months you are probably best just filing for D. I know you're thinking about going into this gradually but legally, I was told by numerous attorneys and a judge that it's best to just go with D. There are specific reasons why LS is the better choice, but I don't recall what they are. Keep in mind, divorce in California can take a long time. The quickest I know of amongst my friends was about 6 months (and that was a simple one, house sold, no alimony or child support because both parents had equal pay and custody), the general time frame seems to be anywhere from a year to two years. Although I do know of one woman who is on year 3 or 4 (after 5 I think I heard that it may become null and they'll have to refile).
There is no arriving, ever. It is all a continual becoming.
