My SO of 6 years has ADHD and is on medication. He went off it for a year when we started dating and he got more impulsive and distracted and did things like get overly excited when we were at a baseball game and yell obscene things at the other team and I almost wanted to break up with him. He also stole spice from the supermarket one day and I told him I couldn't date someone who stole things. He ended up going back on his meds and was better. He has a pretty severe case of ADHD, though. He also seemed a bit emotionally immature when we first started dating but has grown a lot. I think I read that people with ADHD can sometimes mature emotionally slower than others. We were 24 when we first started dating and now are 30.

I don't really know about being emotionally reactive though. For the most part my bf has been really chill and doesn't lose his temper or get really sensitive about anything in our relationship. Does your bf seem to go through very specific periods where he is down for awhile/depressed? Sometimes bipolar disorder can be misdiagnosed as ADHD, or maybe he has something else like depression? Are the lows related to things in his life like your relationship or just happen randomly? Maybe you can convince him to discuss with his pdoc or someone?