Hello I'm a 33m with adhd my former partner is 35f and not

We had been seeing eachother for 9 months. We ended things in July because of some differences in what we want a relationship dynamic to look like. I'm non monogamous and It's hard for me to commit fully (I'm currently talking to my therapist about this wondering if it's an adhd symptom) she in her words, could be open to it but it would be begrudgingly. So we split. The last couple weeks I've had this overwhelming urge to message her and talk to her. Maybe even see if we could make somthing work, I've wrestled with it, and haven't messaged her because I don't want to mislead her or act on this impulse and get myself in to a situation I won't be happy with weeks later. So, like the title says. Am I fixating on her. Is that a symptom of adhd? Are my feelings legitimate?