This may sound like it is too simple to work, but try it.
Count your blessings!
Sit and write down a list of all the good things about your husband for which you are thankful. Then write a list about the things in your marriage for which you are thankful.
Then tell your husband those things!
You may choose to write him a letter. You could even send a thank you card through the mail (who doesn't like receiving mail?!).
You could tell him over dinner. Maybe go on a date so the two of you are alone or put the kids to bed early and have a special dinner. If you think your husband would agree, maybe ask him to do the same and then you can share your lists. Or, you could just discuss it over dinner instead of writing it down beforehand.
In any case, count your blessings. No matter how hard life seems to be at times, there is always something for which to be thankful. If you are in a rough spot in your marriage, thinking on the good things can only help. If your marriage is in a good spot, thinking on the good things will only make it better.
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things.