Allah (Swt) has blessed you so that as you say, everything is perfect in your marital relationship. We would like to commend you for seeking help to deal with the sexual aspect of your relationship. In your message, you are describing two issues. We will deal with each one separately.
First, the issue of talking to your husband about your sexual relationship. Couples often find that this aspect of the marriage is very difficult to deal with. Various reasons have been offered to explain this difficulty: some counselors find that if one or both of the spouses have shy personalities, there will be hesitation in discussing the sexual relationship. In addition, different cultures also socialize people to shy away from discussing matters such as sex or the sexual relationship. It seems that your husband is an understanding man. Choose a time that is suitable for both of you. Suggest to your husband that you want to discuss a topic that might seem awkward at first but that insha allah, with time, both of you will be comfortable enough to share your feelings with each other.
Remember, open and clear communication with your husband may actually help to improve your sexual relationship. Not sharing your feelings will only lead to confusion and sometimes doubt. Rather than having each of you guess what the other is feeling, it is better to learn to talk about it.
Second, you have brought up the issue that your husband desires to have sex more often than you desire to do so. You should be aware that this does not mean something is wrong with you or especially that something is wrong with your husband. Human beings are quite diverse and our needs and desires are quite different. In a marriage, it is imperative that the two spouses try to be mutually responsive to each others needs. As your communication with your husband improves, you can share with him your feelings, your moods. It may be that until now he only sees it as a matter of you being physically tired and not so much a matter of mood.
In time, you will be able to predict your husband's moods. Try to plan ahead and share your thoughts with your husband. Do your best never to simply engage in sexual relations when you are not in the mood. This is not good for your husband or for you. Over time, you will begin to dislike that aspect of your marriage if you do so.
On the other hand, once in a while, when you are in the mood, plan ahead for a special evening with your husband that eventually leads to sexual relations. In this way, your husband will begin to appreciate the time that he spends with you and look past the differences in moods.
Some couples have found it helpful to plan how they spend their time together. It may help to try to find alternative activities that both of you can take part in. Depending on your preferences and the resources you have available, you can choose indoor or outdoor activities.
Finally, make du'a to Allah (swt) that He has blessed you with a stable marriage. And seek help from Allah (Swt) to deal with your husband successfully.
Do write back and let us know your progress.
And Allah (swt) knows best.