My guess is that it's probably a combination of things.
My husband who normally will humor me with my needed cuddle time will dodge me, and try and get out of it in the summer, my body heat is just too much. ( I can't help I'm so hot!!
Also, we do much, much less of it the longer we're together, mostly it's only when I ask for it.....after ten years I think that's normal ~
And also, as far a bipolar goes, I have times that I don't want to be around anyone, not even my kids, I feel bad saying that. But I just need time to myself, to be alone with my thoughts and decompress. I usually find that time either really early in the morning or late at night, the rest of the time it's the usual family chaos ~ which I love, I just need a break from sometimes.
I wouldn't worry about it too much. Relationships do have thier ebbs and flows, and although I wish sometimes things were still the way they were back when we were first together and in each others arms constantly, I know that isn't realistic, and things just change as you get older, and you've been together a long time.
It's nice hearing from you, I hope everything else is going along ok for you guys, and you had a nice holiday yesterday!