Deep breaths! This is devastating for you.
He’s shown you what he thinks of you and your marriage so let him go. Whatever you do, don’t try the “pick me” dance. Give him enough rope to hang himself.
Gather all your/his paperwork together: pension stuff, bank account stuff, passports, life insurance etc. Photocopy what you need to prove entitlements. Take a chunk out of any joint accounts and transfer to your personal account(s).
Ring around some solicitors and ask about their free consultation process. Most will give you half an hour of time for free. Knowledge is power.
This is what Mumsnetters call “Getting your ducks in a row.” 🦆🦆🦆
Husband is hedging his bets about divorce. Not being sure etc. What the hell does he think you are going to do, waiting around, whilst he shags her and makes up his mind? He’s thinking if it doesn’t work out with OW he’ll come back to you. They often do come crawling back so be prepared for that.
Meanwhile if he sees or senses you taking some control (whether you feel it or not) he’ll get a big surprise won’t he? He probably thinks you’re a push over!
In my personal experience I watched my DH’s jaw drop when I hit him with the legal facts of what a divorce would mean. A powerful moment.
Others will come along soon with more/better advice but meanwhile here’s a handhold to keep you going. Show him what you’re made of. Chin up OP.
Brace yourself for a storm but eventually you’ll dance in the rain. Stay strong.