Conflicting ADHD symptoms

I believe that there are different forms of ADHD- that said I am diagnosed with ADHD and believe my husband either has a processing disorder or another form of ADHD.  I tend to be the more impulsive type of ADHDer.  I think things through quickly and prefer to skip explaining the process and just get to the end.  He is the opposite:  he has to process everything out loud.  He takes an inordinate amount of time to do anything outside the work realm. He easily takes twice as long as an average person to even get dressed.  Which means he takes about three times longer than I do.  Our conversations are painful because he has to process everything, one step ata  time, without being interrupted.  I want to interrupt because I want to talk about the first topic- if he goes past that I forget what we are talking about to begin with.  He has been known to go on for 30 minutes at a time.  even using a note pad to keep track, I get cramps in my hand!  I have made every effort to slow down- somewhat successfully- even if it means just going in the other room so I'm not glaring at him.  He seems incapable of speeding up at all.  he resists the notion that he has any attentional problems.  I encourage him to drink more coffee- at least then it's a bit better. I try to keep our differences in perspective.  He struggles with this and gets mad at me. Any suggestions on how to reduce the tension between us?