Marriage can be very difficult at times, and anyone who has been married for longer than a week will tell you the same thing. It just is. This year my wife and I will be celebrating our 10th Anniversary. I'm pretty excited about the last 10 years, and even more excited about the 10, 20, 30...well, you get the idea.
Let me tell you, my marriage is fantastic. I know it from the inside out, obviously, and I've never seen another marriage which I would compare. Most of this has to do with having a wife who is extremely gracious, forgiving and patient. Frankly, I feel sorry for other married men for having to settle for less than the best.
My best marriage advice has, for us, worked well. I'm not saying there haven't been bumps along the road, but they have always drawn us closer together, not further apart. So this is my advice: Focus on Jesus. In my life, my wife is the second most important person, and she wouldn't have it any other way. I am the second more important person in her life, and that is how I want it as well. Our top priority is Jesus Christ.
In Scripture Husbands and Wives are given some commands, like "Husbands, love your wives as Christ loved the Church and gave Himself up for it." Then it tells wives to "submit to your husbands", even to respect them. Let me assure you of something; our marriage isn't this good because my wife always earns my love, and it certainly has nothing to do with me earning her respect or submission. I have failed many times in the last 10 years, as has my wife. There have been times when loving her was difficult, and when respecting me would have been impossible, but for this one thing; we don't love and respect because the other deserves it. We do it because God told us to, and He comes first in our lives.
Many times people struggle with this, but I believe this is a strain not in their marriage, but in their relationship with God. If I love God with all my heart, mind, soul and strength, I will love my wife whether she deserves it or not, because loving my wife is an act of worship to God! That is the long and short of it. So when I don't love my wife the way I should, I am failing in my worship to God. Now, maybe she did something she shouldn't have, said something hurtful, or didn't respect me the way she was supposed to. But my love for my wife has nothing to do with that, and has everything to do with God.
Therefore, when I don't love my wife as I've been commanded, I am committing idolatry. I have chosen to worship self rather than God. As hard as that may seem, it is the truth. A tough truth, but truth nonetheless.
So my advice? Love God with all your heart, mind, soul and strength. Put your marriage into that framework, and see what God can do for you and your marriage.