We all change the oil in our cars (or get someone to do it for us). Why do we do this? Is it broken? No, we do this for maintenance...to help us prevent major damage in the future and prolong the life of our investment.
We should be doing the same thing for our marriages. What preventive maintenance have you done recently in your marriage? I tell couples in both my professional and personal life go to counseling at least once a year together. Not necessarily because your marriage is broken, but to seek out areas where there may be a lurking issue. If you get a good "bill of health" after the counselor looks under the hood - great! See you next year or sooner if something starts making a weird noise.
So often, couples come into counseling after the engine is falling apart and they ask "Can you fix this?" The answer is maybe, but it's going to be a lot of work and I sure wish you had come in sooner.
Your marriage is a huge investment. Take care of it. Get some outside perspective and the relationship will serve you both well for many years to come.