DO NOT GO THROUGH THE CSA
I repeat – DO NOT GO THROUGH THE CSA
If possible arrange something with the Mother. They are an incompetent bureaucratic machine, once they have so much as your name there is NO escape. You will have payments missed/forgotten and then clamed for later. You will get threatening letters, aggressive phone calls. You WILL be treated as the bad guy.
Ignore this warning at your peril
If it really does go the splitting up/moving out route, try and talk and come to some agreement with her. It will work out far better for everyone in the long term.
Good luck, it's never going to be fun.
Keep your head up and ride your bike. It helps.