A calm request for child support and a schedule is not going to make him go file for D. Not asking is not going to prevent him from doing it. Very little you do can make him do or not do anything - you really have no control of his actions at all, only your own. If anything, it may snap him back to reality a little bit, that he realizes he won't be able to continue eating cake.
*He* is the one who has moved out, started a R with OW, has changed the rules. There are consequences to that, M is a legal contract.
Don't feel bad for still wanting him, those feelings don't go away with a snap of the fingers. You two have a history together, a M, children. He has been processing this for a long time, you just found out.
This is what I needed to hear today. In my head I'm like doing nothing maybe he will not file..but I need to stop worrying about him.