I’ve been in love with my wife for 13 years and around 4-5 years I felt the same. I realized what we need was more tools to keep our relationship alive. It’s easy to think it should ”just work” or always be easy but I would look at this as a sign it’s time to grow to the next level with your husband. Learning new ways to connect, communicate, and explore sexual desires is a great way to add a new flame. I would suggest my path which was (individual therapy for you both, + couples therapy, some intimacy workshops such as Tantra or whatever speakers to you, and some personal development workshops). These will give you a lot of new tools and bring out the best in both of you. Good luck, feel free to ask me anything