How to succeed at relationships?!!!

How do you all succeed at relationships? I'm really good at them at the beginning because I thrive on novelty, etc. However, I always lose steam (interest) around the two-year mark. On top of that, I have a bunch of quirks that I'm not so good at masking after awhile. For example, I'm pretty rigid about certain things, which is a maladaptive coping mechanism to manage my ADHD. My rigidity obviously drives partners away. Also, I get emotionally dis regulated over small things.

I've done a lot of work on myself, so I'm more calm and self-aware. However, my rigidity and emotionality pushes partners away. My current partner is also ADHD, but he's untreated because I think he was traumatized by having to be in the medication line in school as a kid. He and I are a lot alike, which can be good and bad. Regardless, I still feel like I can't do relationships.

Can people with ADHD do long-term relationships?!!!