Flotsam

[skyhigh]

Interview a few lawyers to find the right one to you, ask around you for references.
Don't give your WH any potential information about your next moves also he might try to be "nice" (let's be friends...), just to appeal to your emotions to get something that he knows is not in your best interest. Don't be fooled! When they file it means they are ready and organize already and thought about all their moves.

Document everything, stay polite but distant!
Separate your phone account if it's to your advantage so he doesn't know who you are calling.
Change your passwords put a password on your computer/iPad... check if he put any software in it.
Call the bank and make the necessary changes if you gave him any power of attorney or administrative rights.
Take pictures of everything you have, he may or not remove items from the home when he will move with or without your approval.

Ask for a temporary alimony and a child custody orders if you need them. Show him that you are ready to stand up for your rights and not going to accept whatever bones he will give you to chew on it. He might think he still can manipulate you by appealing to your feelings (be ready for some surprising affectionate moves...).

Copy any legal documents (retirements, accounts, investment funds...) you can have, follow the money trails, sadly from my experience (a few friends), before filing the H hid money somewhere.
Remember also a marriage is a financial partnership so if he spends money on the OW, you are entitled to be reimbursed 50% of it (that's what my lawyer told me...).

Doing all of that doesn't mean you want a divorce it means only that you are protecting yourself. Knowledge is power. The more knowledge you have the better you will be have to navigate the months ahead of you.

Limerence and its fantasy land don't do very well with obstacles, so slowing down the process in a very clever manner can be an advantage for you.

Tell him that you are not going to share his version why you are separating with others, since he filed you are now free of expressing your side. MLCer don't like to be seen as the bad guy, they have a high opinion of themselves.

You might want to expose him and his affair partner if he has one... but only if you have proof, don't do a full exposure but a targeted one, just to show him that he is not fooling you anymore, that you are way smarter than he thinks. I did that... they hated it. It disrupted their la la land, being seen as a home wrecker or a cheating husband is never good for your own image in regard of others. It's up to you, each situation is different but I noticed that exposure is a way to shake the situation, it brings the secret relationship to light and it removes some of its "excitement", by forcing them to deal with actual facts and making decisions.

Something not to do, begging, crying, trying to negotiate.
Stay detached, keep your eyes open, trust your guts and avoid any confrontation or to send him anything he can use against you to try to picture you as unstable.