Hey K.. Sorry to hear about the pain you are going through right now.
I have been on the other end of this stick. I met a man and left my husband, late night phone calls etc was all included. Point is not that I did these things but why. For someone to be attracted to a person that is not their spouse, they have to have already lost most of their feelings for their partner. Think about this!
When I met "the other man" my marriage was OVER. I had been asking my husband to leave for months and we were miserable. Sometimes it's not a big fight, there isn't a definitive moment when its "over". Many times its less tramatic than that, sometimes you just don't talk and slowly the feelings fade, and maybe even resentment starts because you AREN'T talking.
I had lots of time to think about why I did what I did and all. I basically came up with this. I was really miserable, I was dying. The person that was supposed to be the other half of my soul, my mate cared nothing about who I was anymore. I know the feeling of cardboard you spoke about. You feel empty, hollow, cookie cutter. Every true part of who you really are is so buried deep inside and wrapped up in a safe place that you almost can't find it anymore. Anyone that listened to anything I had to say, any wisp of interest in the little bit of who I was immediately got my full attention over my spouse.
Its easy to get into "Mommy and Daddy" mode and that is all that we were. We were parents, no longer spouses or lovers or friends. I couldn't think of anything to talk about, not even chatter. When you start talking about the weather cause thats all you can think to discuss something is wrong. If all you talk about is the kids, something is wrong.
I hope counseling works for you, we went and it was a joke. Maybe we just had a bad therapist. She didn't want to discuss our issues or help us truely communicate. She just wanted us to "plan our dream date" and "do something special for your partner". Our problem is that we hadn't talked, really talked in so long we no longer spoke the same language. Things he was saying were really important to him were the least concerns on my mind. Maybe if we had gone to counseling before it got to that point it would have worked.
There are a few things my friends asked me to do while I was getting ready to leave my husband that really helped me.
1) Make a "man list". Forget your husband, forget the old boyfriends. Make a list of the things that hurt the most right now, things you are missing, things you thought your spouse would be when you were starry eyed and in love. Write down a list of at least 15 things that you "require" from a man. Next order then in order of importance. (My list went from being able to understand and discuss feelings to not being a wet kisser. Nothing is too important or too silly.)
Share this list with your husband during counseling. Let him know that these are the things you need from him. Tell him why these are important to you. Ask him to make a list too and share it with you.
2) Next my friends asked me if anything I wrote on my list could be fulfilled by friends instead of my husband. This is an insteresting question and one to ask your husband about his list too.
This list was very eye opening for me, as I left my husband and moved on it became more important during dating. My number one requirements are that a man have, understand, and discuss emotions regularly and with eye contact. Grunts, I don't know, and sighs don't count. (My current boyfriend meets 15 of the 16 I wrote down and I don't think wet kisser really breaks the deal since it was last on my list! He is aware of this one fault and tries very hard! LOL)
Pondering if other people could fill the gaps for me was the key and I actually took several months to respond to my friends as I pondered the question myself. My ex was an emotional black hole. He had three words for feelings, angry, ok and sad. Thats it. I decided for me that my soul mate, my partner had to be able to share the entire gammit of emotions with me and enjoy and despair in life at my side. This was not something that my girlfriends alone could fill in my life and it was #1 on my list.
Maybe your list and his list will have some similarities, maybe it will help be a tool to get back to the basics and the foundations of your marriage. Its all up to you though, you have to be willing to forgive him, completely and allow him to rebuild your trust. It can happen but it will take much time and alot of effort on both of your parts.
Hugs,
A.