mineis,
If your husband doesn't feel anything, does that mean your marriage is in trouble, in the sense that it may not last? No necessarily. With the typical American spouse, it is. If you were from India in an arranged marriage where they don't think marriage is based on feelings, it probably wouldn't be.
I wish I could think of a book specifically on marriage that drives home the point that marriage isn't supposed to be based just on how you feel about each other. It is good to have romantic feelings, passion, etc. in marriage, and couples should cultivate that, but if you go through a dry spell, that's no reason to get a divorce. That may be something you could discuss with your husband.
Sometimes people go through 'dry spells' where they don't feel as close to God. Normally, it just feels like God is answering their prayers, but they just don't 'feel it' at other times, and don't have the same joy. A mature Christian can maintain his faith in the desert. He knows that feelings aren't everything. It's good to have good feelings, but our relationships shouldn't be based on them.
Part of love is commitment, too. You could just talk to him about this and see where his thinking is on commitment and if he needs some help in the way of teaching or encouragement in the faith on that issue.
It feels a lot safer in the marriage when you just know both you and your partner are committed to staying married. If the emotional fire dies down, then you know you and your partner will both stick around and work on relighting the fire or stoking it with some new fuel. If you are both on the same page that you work through his emotional funk and stay together, that may give you some comfort.
Several years ago, my wife told she didn't have feelings for me. We'd moved and she later said she was experiencing culture shock. She was grumpy quite a bit. She's also said that sort of thing during bad PMS experiences. Then later, she'd hold me and tell me how much she loved me. So it's not necessarily permanent.
Something I'd suggest is regular, preferably daily, prayer together and reading the word together. If you don't do Bible study together every day, you can still pray together. I've read that though professing evangelicals divorce at about the same rate as the world, less than 1% of married couples who actually pray together regularly get divorced. You can directly pray for his problems. Pray that he will feel more love for you, that he'll feel the love when you are intimate with each other, and for the Lord to work on all these problems.
It may be a hormonal thing, but if my wife is very generous in the physical intimacy area and it's more frequent over a period of time, it intensifies my feelings for her. The verse in Proverbs 5 about a husband always being enraptured by his wife's love is in the context of discussing a couple's sex life.