Too many people think that someone being 'nice and kind' is enough reason to spend a lifetime with them. That is a pretty low bar.
However, this is not the 50s where you needed someone to financially look after you and the kids - so not abusing you and not cheating was something to be grateful for. Now, many women want partners who they have more of a connection with, someone who they could spend an entire weekend locked up with and not be bored senseless. So you are not asking for much.
What you have described is that you and DH have just grown and evolved in different ways - and his lack of interests, hobbies and conversation is leaving you lonely and unfulfilled. That is a good reason to leave. Meeting your friend has shown you that different types of relationships do exist - he has such a marriage, and it has opened your eyes to what already sensed was missing before. It is a sad fact of life that people do change, and with it, so do relationships and marriages.
It will hurt your husband, but it will be hurt far more for him to spend the rest of his life with someone who wishes he were different. Before you make the decision, see if there is any way to get him to develop his own interests or hobbies? If you have tried, and he simply is not that way inclined, there's not a lot else you can do.
It is a hard decision, but ultimately one that is best for both you and him. You may never meet the type of man you want, but at least you will live with the hope, and can make your life how you need it.
For what it's worth, I left my marriage to a nice, kind, supportive man who I had never been that attracted to. I always felt like something was missing. After I left, I had relationships with men I did have that attraction to, and though they didn't work out, the relationships were no worse than the marriage I had left. In fact I had felt much happier in them and it showed me how much I valued physical attraction. It was the thing that made it easier for me to compromise and enjoy the relationship more - I was a different person in those relationships. Nicer, happier and more full of life.
My current relationship is with someone who is nice, kind and I am attracted to him. Not once have I regretted leaving my exH. He is with a woman who loves him more than I did, and happy. And I am happy not having to compromise on something important to me.
Good luck whatever you decide! 