Don't mention it.

I think that I understand what you are conveying in your statements, but it is possible that my understanding is how ever limited and/or that I am misunderstanding.

I was trying to think of possible causes to list for you to think about and decide for yourself (in an attempt to assist you to how ever a degree if such an act were not redundant.) Moreover, I would not attempt to decide for you in general and/or tell you how your perspective is, how your emotions are, why you have the perspective that you do, why your emotions are as they are and so on.

As you are indicating, "empathy"/"compassion" or how ever it might be labeled seems to be a/the main source of why you are feeling sad. Additionally, as you verified, in the present, you seemingly appreciate an aspect (e.g. his mom) of your history/relationship.

Just to clarify quickly, the last suggested factor was not necessarily still "having feelings" for him, but more of some attachment to him/the relationship (even if it is minuscule) while still acknowledging the rest of the content of the relationship (e.g. abuse) and acknowledging that the relationship is indeed in and of the past (and will stay there, unless you choose otherwise.)

Again, I wish for you to be well and empathize with you.