Welcome to our forum.
It sounds like you and your husband have evolved in different directions with regards to what interests you in the bedroom. One of the nice things about polyamory and open relationships is that one person doesn't have to be the end-all be-all to one other person. Different people can meet different needs.
You will find that there is much good material to read and study on this site. The Golden Nuggets board
will guide you to some of our especially useful threads. Now that doesn't mean you can't post, especially if you have a question to ask (or even a thought to share). It's up to you and has to do with what you are comfortable with.
I think it's very normal to fall in love, and people can't always control or predict what their feelings will be. It sounds like you are looking for a new relationship with some depth of emotion.
Take your time and get comfortable with the ins and outs of polyamory, but I think you'll find that polyamory is a good lovestyle for you.