Just bringinng this thread back to report to the group. Things are much improved.

I've spent the last few sessions working only on rhythm, and on songs with strong grooves rather than heavy technical elements. Overall, he's taken a step back with the attempts to out-shred me and is offering up some nice soulful blues... much respect.

I think I've also identified that he's trying to 'beat' me when we play together, so I've taken it down a notch with him and it seems to be working. He's sweating less and smiling more, and I've learned a lesson here too...