Hi brother Doug,
It is interesting that you are posting this because I am working with a young couple right now and they are struggling with similar issues.
I am not a marriage counselor but God can use anyone who loves others and walks with God. So my approach is as follows:
1) Do both parties want change? If not then it is really about helping just the one person who wants to change and praying for the other...lots and lots and lots of prayer.
2) If both the husband and the wife want change then that is fantastic. In fact I would say that if they both do, then the Lord is working on them. If they didn't then this would indicate hardness of heart and there is a hard road ahead for them. Perhaps even separation and then divorce.
3) If the couple both want help then I want to help them understand that they cannot expect a different outcome by just continuing to do things the same way over and over again. Change is needed. If they both agree to change and to do whatever is needed then we can move on. If they do not then we must stop and find out why they are unwilling to change.
4) If there is one party (which sounds like your situation) who is stuck, they cannot see anything positive any hope because they are so mired in past hurts, then we have to camp here for a while to help them get unstuck.
5) And this brings me to the third party counselor, which is the role I am assuming in this case. Many times when couples are stuck they need to change things up and "call a friend". We use the word marriage counselor but it is really a godly individual whom they both trust and who is completely impartial. I would say that the main role is to be a mediator. Ask questions of one party and then go to the other party...keep them both talking to each other. The counselor should also step in if it gets heated or one party is taking it off track and getting bogged down. But yeah, I highly recommend a third party as a last(?) resort if all else fails.
6) On top of this I would want to know if the couple are in some kind of fellowship where their are other godly believers around them who love them and pray for them. This is such a great help. I will always encourage this.
7) Is the husband the spiritual leader of the family? I don't mean is he the one with the most knowledge, but is he "leading out"? Is he seeking God, or at the very least wanting to seek God lol:-) If he is not then this is where he needs to start. He must put God first in His life and the rest will follow suite. But this is where fellowship comes back in. I cannot tell you how important our house church fellowship is to me and the rest of the brothers.
8) Unforgiveness and grudges. This is soooo vital to deal with. This is fundermental to our faith, to our very walk in Christ. If either couple cannot/will not forgive the other then this has to be gently looked into and worked through. This is where the leading of the Holy Spirit is so vital. I pray a lot before, during and after my times with couples because only the Lord knows their heart and can open them up to the Truth.
9) Regular sessions. I am a believer in continuing on with meeting with couples who need help so that issues can be addressed and followed through on until they are dead and buried. One thing that is so important to get spouses to see is that it is unloving to be sure for the husband to be the way it is, but it is also unloving for the wife to be impatient with him and to keep a record of wrong.
In it all my hope in meeting with couples is to help them see that the goal of their marriage is LOVE. Thats it, pure and simple. How can we as a couple love one another as Jesus loves us? If they can leave no stone unturned in their quest to get to the bottom of the LACK of love in their marriage then God will surely help them.
So, the bottom line is if we have been struggling ALONE with marriage issues for many years, then perhaps it is time to get additional help. That takes courage and humility. I want to encourage you brother that opening up here is a very good start for you.
God bless you and your precious wife!