Talk together about what you like about the marriage. Be the first to begin. Make it fun and without pressure.
Creating an environment between you that is positive and loving has the greatest possibility for increasing intimacy. Spouses want to be closer, both emotionally and physically, to those that they like and enjoy.
Focusing more on what is good about your partner and your marriage, rather than the negatives and struggle, are much healthier and much more likely to lead to the results that you want.