Most of us here it seems, when we're a bit unfair, resentful, controlling, whatever...it's evident and we are offered that mirror. Not saying you're perfect, but I've hardly read one word from you in months that doesn't come from a serene, well adjusted place that you've worked very hard for.
Non-compatible doesn't describe a 15 yo R. That was a stupid thing for your H to say, and it's jackal speech from me, but it's dishonest.
If things got dull with you guys, well...you're both responsible for putting in the work to be interesting ppl and interested in ea other. Sexually, emotionally, mentally. It's hard stuff to maintain.
If you find you want to give it one last attempt, IMO - why not take him on a date and see if there's anything left to re-kindle or that you want to. Sure, maybe it opens up wounds that have scabbed over, but courage is action in the face of fear.
If there is something in your gut that knows better and you don't want this, and you're ready to accept new love and romance, I think you have a lot of room to be at peace. Your H was a fool to have left. He's a bigger fool to not return.
But - I pose this kindly - how can you know either way where your heart is when you're trying to decide from memories of him/your M? People do change, are always changing. Don't you wonder who and what he looks like to you now, in the present?
Mid 30's Psych-abusive M with violent tantrums from XH D 9/15; NC forever on