I'm sorry you are going through this.
Many marriages go through "slumps", then that slump leads to a total disconnect. And that's where your marriage. TOTAL DISCONNECT.
Start dating each other again. No cell phone, iPhone, iPad, Laptop, etc. just the two of you.
Start a family night where you COMMUNICATE and play games - and make it part of the routine. Wednesday night is family night in our home. We play games or we watch movies.
We eat dinner together every night. We TALK about our days at the dinner table. I am not going to say my marriage is perfect, it's not. But it works for us. Divorce isn't in our vocabulary. We have never put it on the table. Have I thought about it once or twice? HECK YEA! Even the strongest marriages go through strife.
It's a step in the right direction that he wants to go to counseling. He told you the truth - and sometimes that's REALLY hard to hear. But in my opinion? I think it comes from being disconnected from you as well. It's HARD to get back together after being distant. If YOU WANT it work? There is hope. Both of you need to want it to work.
Remember - this is the example you are setting for your children and their future spouses...it's obvious you don't want this for yourself, let alone your kids.
the marriage counselor will probably tell you guys to start from scratch. Dating each other. Writing a list of things you love, like, don't like and hate about each other and if they are deal breakers in your marriage. You MUST communicate. As hard as it is to hear some things - COMMUNICATE. Set rules for fighting - no below the belt things, don't bring up the past - you can't change it - you can only learn from it. Don't keep doing the same thing - it's not working so don't expect something to change when you are doing the same thing.
Tell him your expectations. Be prepared to hear his. You both can do this!!
GOOD LUCK!!