It's not much consolation but you are not at fault at all. Having an affair is a personal failure, not a marital one.
Honey, she may be younger, and all that, but his choice to have an A with her or anyone else isn't about you. It's about his broken soul. He has a need that he is trying to fill with others, and is too shallow to see that he is the one that has to fill that hole.
Yes she is young, but you are not old. You have a full life ahead of you, and you can make a choice right now if you want to continue to live if filled with pain, hurt, and dishonesty, or if you want to walk away from it, and find happiness in yourself, in your life, and be free from the worry, and agony.
He has shown you not once or twice, but three times, now. You deserve more, demand it.
Go see a lawyer, and file, and would strongly recommend not looking back, no matter what flowery words he showers you with.
Read the healing library, read other posts, in this particular forum the ones with bullseyes are a good place to start.
Keep reading, keep posting. We are over 40K strong here.
Your first priority now needs to be you. Eat when you can; sleep when you can and keep those fluids up so you can think straight.
Did your WS put the work in after the last A's or did the A's get rugswept?
If he didn't do the work to find out why he keeps having A's then he won't have the tools to stop. Also, if you rugswept there were no consequences for him o, in his eyes, he probably doubts deep down that you will leave him.
Two things struck me about your post.
The first is that the OW brazenly was at your house and just so happens to get ill so she can sleep over?
I don't buy this- I think she (or they) planned it.
The second is the fact his second A carried on for 2 years after you found out. Did you know this or did he take it underground? If you knew but were hoping to wait it out then you have given him a message that there are no consequences which may be why A number 3 has come along.
BUT-BUT... these A's are NOT your fault.
You could have been a supermodel in looks but he still would have cheatedbecause the issue isn't to do with you or how you look or act. It isn't about what you did or didn't do.
It is about him having something broken inside of him- so it is his issue not yours.
My advice to you (if you want any decent shot at your M) would be to throw him out and initiate a 180 (look in the Healing Library for details)
Once you can see in his actions that he is remorseful then you can decide what you want to do.
My fear is that if you don't take a hard line straight away then the pain of this will just get prolonged for you.
You don't have to decide what to do immediately but you do need to decide that you are worth far more than being a wife who gets cheated on.
You are better than what he has offered you up to now. Trust me on this.
If it helps, I did kick my spouse out for 5 weeks. It did me wonders to not have to look at him each day. And I realized I can do this on my own. After 27 years, I honestly wasn't too sure.
Now since him returning, we have split up again several times. But a lot of that was it just gets too overwhelming for me and I ask him to leave. Both times have been shorter lengths but this road is not easy.
Please do what you need to do to breathe. That is truly what it comes down to in these early days. When I forget that, is when I start to feel overwhelmed.
I still don't know where my marriage will end up, was this another chapter or was this the last chapter. I think that still has to be decided. So take your time and breathe.
Do what you need to do today to get through it.
Hugs and prayers to you.
Her: WW/57 Me: BS/63 24yrs M
3 great kids, now 22, 20, 17 b,b,g
D-Day 8/14/08, D 1/13/11