I think "you're better off without him" and "it will get better" are words that are true, but also words that mean almost nothing to you at this point.
None weeks is nothing. For the first three months after something similar happenned to me, I was in medical shock. Years later now, I don;t actually remember a year of my life.
Autopilot goes on.
For now. Be practical. Find the steel core inside yourself and whisper internally "this is not going to beat me" and make the decision to cling on to fighting for what's best for you.
Do that by getting the right legal advice, making sure you are protected financially, making sure you do not allow your battered self esteem to make you forget how important you are.
"when people treat you like shit, it has nothing to do with you and everything to do with them". Repeat that over and over, every morning, every night every minute because it's true.
As for the pain...yes...it gets better. I'd say it gets better in the sense that you find yourself a while getting through an entire day without remembering it. Then an entire week. Then it's just occassionally. When you do remember it, it hurts just as much - but it's no longer present.
Recovery times are largely dependent on you. If you find ways to fill the time with things that make you happy and build your confidence back, you will feel less "loss", less "need" and you will find a place where you actualy believe "you're better off without him".
My best advice after such betrayal and shock, and being disgarded like rubbish by the person you loved and trusted most in the world is to find a way, by WHATEVER means, to truly believe that when someone behaves like this is is NOT YOUR FAULT. You are not defective, you could not have chnaged it by being better, younger, thinner, dirtier in bed. OW is not better than you. She is just diferrent. JUST DIFERRRENT. And he might well do the same to her one day because it's in him to do so. He has taken something from you here and you will need to fight your way back. Do it. Because fuck him that's why. Because you're a loyal spouse and he isn't. Because in time you'll realise you dont want to grow old with someone capable of that.
My second best advice is to get it out. Don't lock it inside, don't stop talking about it. Talk to anyone, everyone and cry and scream and drive your friends and family mad - because that grief is very real, few people will understand what it feels like to lose a husband in nine weeks...and if you try and push it down it will come out later in ugly ways. You deserve better than that.
I am so sorry x