I liked the idea but always went back to "nah I'd rather spend more time with my H"
I hear you. That has been my mode of operation for a long long time. I actually turned down sushi with my W the other night to go hang with my B....it was so hard! But, I've always been available to her so I'm trying to do less of that.
And you don't have to necessarily find a new friend right out...just try new things. I went to a wine tasting by myself last night and while I was a little uncomfortable at first (my W is the more social of the two of us), I ended up having a blast and got a nice ego boost from the fact so many women found me interesting.