Oh dear. I apologize in advance for what's turning into a lecture as I write.
You're seeing the difference between love and romance. Romance is exciting and fun and a little of it is always nice to have!
But love is what's there even when the romance isn't. It's what you really want, because it's solid. You can trust it! If love is a meal, romance is the appetizer. It's tasty, but you can't live on appetizers. Do you really want to? Wouldn't it be better to make the meal more nourishing?
There are a lot of reasons why the blahs happen, and they happen in many marriages, if not most! One is the fact that there are only 24 hours in a day, and you have more to fill that time with than you did. Another could be because you both are physically tired! Yet another - and this is a big one - is that busy people let communication slide.
Some of these you can do something about.
If you have some deep emotions that get in the way of working on this relationship, you yourself can seek counseling to get those worked out.
You can play a game with yourself (don't tell anyone!), pretending that when you see your husband you're seeing him as another woman would. Don't assume you know him; look for things in him to like.
Again, without saying anything about it, say more words to him. Say "good morning" if you don't now. When he comes home and you're there, or vice versa, go and say hello to him, as if he were important. Use the good manners you'd use for the neighbors. How many married people don't even say "please" or "thank you" to one another? A lot, I think. They take each other for granted. The other person disappears. They don't even think how special he/she is.
"Hoping things change" is like wishing on a star - it's not real life. If your marriage can use a boost, it may as well start with you since you're the one concerned about it. And you need to as well because your husband undoubtedly has a different idea of a good marriage than you do.
You have absolutely nothing to lose by doing some little secret things like this. When your husband starts noticing what you're doing (it takes a good while with some guys!) and starts feeling good about it, he might decide to make a few changes himself - but don't expect it, demand it, or whine about it. Whining is anti-romantic.
Feelings are facts, but feelings don't always tell the truth. Folks who give up what they have to find feelings they've lost often end up with feelings they wish they didn't have.
OK. End of lecture. :^+