To the OP
I agree with writing to him and clarifying your side.
At worst you both have closure, at best a window opens.

Just don't do it with any expectations attached.

A few years ago I sent my ex a similar email, except I not only apologized, but explained that I understood why HE LEFT ME (my badly managed MI was bleeding him dry) and that I was glad he had the good sense and self love to save himself.

He replied with "see you in 20 minutes" and we've been inseparable ever since.

Point is, I wasn't expecting anything. A year had already passes and idk, I finally "got it" and I wanted him to know, and luckily that lead to something better than closure.