After one week of NC he was a complete emotional wreck, unable to function, saying he felt like someone had died.
Classic blameshifting..."You made me stop talking to her, now I'm a complete and total mess." Baloney.
Very gently...this is normally what the betrayed feels like, and a WS who is beginning to come out of the fog. He couldn't deal with it, so as soon as you gave him the nod to speak to her again, he went with bells ringing. Right now he has his cake and eating it too, because he's getting to talk to her and come back to you, and he knows you're not going anywhere so he has zero incentive to change. It will only change when you get fed up and tell him you won't tolerate any more...and mean it. If he's speaking to her, soon he will be having sex with her, if he isn't already.
Showing him love letters from the past will only do one thing, and that is reinforce in his mind that you are not the same person he was writing those letters to, and give him another reason to justify what he's doing. There is no reasoning with a cheater who, by nature, is automatically going to do and tell himself ANYTHING in order to justify his actions, and those things are usually absolutely untrue. Whatever keeps the fantasy alive in his mind, and whatever makes you look bad to him, he will say and do. Showing him the letters will allow him to tell himself that you are weak and pathetic...and that is NEVER attractive.
I am totally with NoReGrets here: would he be begging, wallowing on the floor and unable to function if you cut off all contact with him and left the house? I'm willing to bet that the answer is no. Just a gut instinct.
No contact with her = they're not able to spew their sweet nothings at each other, talk trash about SO's (does she have one?), and ramble on about how their lives would be just perfect if only they could be together forever...not getting that emotional high they get when they're together. So yeah, he feels like he's dying emotionally because he's not getting his ego stroked and sweet lies told to him and to be blunt, getting his ass kissed. That is the fog, all rolled up in his sick mind. And until you clear that fog for him, all this bullshit be believes to be true will never go away.
No contact with you = he won't feel nearly as bad about that as he does about not being in contact with his AP. He might be upset, but not the heart-rending, writhing on the floor, my-fairy-tale-is-ending kind of misery he's displaying for HER, the one who is not married to him!
Right now, you're in denial. That's normal. You're not ready to give in to the kind of anger that it takes to stand up and demand that you be treated right. It will be up to you to say, "I deserve for you to love me, desire me, feel for me, and treat me...the way you treat HER. You are married to me, and I am not willing to be second best in my husband's heart." That's about respecting yourself and standing up for yourself and your marriage. And sometimes that means you have to be willing to let your marriage go to make your WH see that you mean what you say. You'll have to get to the point where you tell him that if he won't choose you, then you have to choose yourself, and move on.
Ask yourself: Are you content being a willing participant in an open relationship? Because as soon as you gave him permission to break NC with her, that's exactly what you became. I'm not trying to be harsh. Believe me, I spent an entire year trying to rationalize how my H's A was my fault. I lied to myself 258 ways to the sun. I was such an idiot. I even asked my doctor if I could have gotten herpes off a toilet seat. He just hugged me, and told me that I would have to come to grips with it, and he was there for me with answers to any medical questions I might have. That is why it sounds like I seem like I'm coming down on you. You sound just. like. me. You don't want to believe that this awesome guy could do something so unbelievably wrong to you. You want to believe that guy is still in there somewhere. He might very well be, but you've got to get him completely away from her before you can even TRY to get that guy back! He won't even be able to find that guy in himself as long as his AP is in the picture. Right now, he's too busy being HER dream guy.
Does that make more sense? To us old-timers at SI, when we see you asking if you're not supposed to tell him "I love you" back, the answer is, no, not as long as he's still seeing his AP. When he says that to you, he's trying to trap you and making sure you will say it back so then he knows you're still firmly in your M with him and he can go right on and have her too, knowing that you'll still be there no matter what dispicable thing he does.
One last thing, something else you said struck out at me...
I told him it was ok if he kept talking to her, so long as he didn't leave. I'm not proud of that now, but I can't un-say it.
Yes, you can! You can sit down, make him a list of conditions for him in order to stay M, and tell him that after careful consideration you cannot allow contact between the two of them to continue. If she has a SO, now would also be the time to tell him that if he doesn't stop seeing her, her SO will be finding out. Do you happen to have copies of those facebook chats?
Stand up for you. You deserve it. And you deserve to not be married to someone who will continue to do this to you. You're a better person than that.
(((((Hugs)))))