Psalm 37:4 ~ Delight yourself in the Lord, and He will give you the desires of your heart.
Are you separated or in a highly stressed marriage, but long for a wonderful marriage with your spouse? I encourage you to do everything possible to "delight yourself" in the Lord. During our separation, I never perfected this; I went through times of anger, rage, depression, and hopelessness, but when I made a choice to delight myself in the Lord, in spite of everything, I had more peace.
Each person is different, but here are some ways that I delighted in the Lord. Taking a walk on a beautiful day, smelling the flowers, listening to the birds - marveling at God's creation could refresh me - even if I didn't actively pray. I spent alot of time at lakes and parks. In Psalm 23, David says that God will lead us in green pastures and beside still waters.
Sometimes when I was out of sorts, I would take my CD player and put on worship music. Many nights I fell asleep with my headset on. I so appreciated worship music that was based on scripture. Some of my favorites were John G. Elliott and Twila Paris. I was often encouraged by worship at church and felt closer to God.
As you chose to delight yourself in the Lord, He promises that if we draw near to Him, He will draw near to us.
I think you will find that the more you delight in the Lord, the more you will know your next steps in loving your spouse back to your marriage. You will know which of the many resources I have listed or others have are for your situation. When you interact with your spouse, hopefully as you have been refreshed by God - they will see a new you - one who interacts with them in a more loving way.