Thanks for looking in: We seem to be just about exactly in the same place with our H's.
I think my H also retreats and gets cold when I don't show sufficient interest in him.
I get torn between the idea of going dim/dark/letting him go, and the need to be nice to him to make him see what he's missing.
In his case, too, just being 'nice' isn't enough. He needs to be slathered with positives. But then, too, he is fundamentally suspicious of my motives, I think.
So he wants/needs positive affirmations, but doubts that I'm sincere/he's worthy... and so the pursuit/distancing dance continues.
But if I go dark, he mirrors and gets nastier.
I find it very interesting that your DB coach has said "be nicer to him".
I'll give this a try and see if it works, while remembering to remain as detached as I can.