I am happy with my marriage in general. I am very unhappy with the lack of sex in my marriage.
A lot of people seem to have trouble understanding how both statements can be true at the same time. Perhaps the statements are both true for us because, if nothing else, we learned in therapy how to keep our sexual differences from needlessly spilling over into other areas of our life. Some of it has to do with developing a genuine ability to see your partner's lack of interest in sex as just "low libido" rather than a lack of caring or love for you.
Yes, I realize most couples would be yelling at each other in my situation and their marriages would spiral out of control. That's what we've learned not to do. It's understanding the value of all the things we have left besides sex. Newlyweds and people who've never been in a relationship don't seem to understand that. Ask any single person what they'd do if their future partner cheated, and 99% of them say they'd dump the idiot. But when and if the reality hits, many realize it's not that simple.