Son asked if I still love mom and I didn't know what to say

He's 8. We were driving to school and he just asked it out of nowhere. I told him I love him and his mom is a great mother and we just couldn't be together as husband and wife but that doesn't change anything. Did I handle that right? My ex and I had a rough split, there's still some anger there on her side especially. I never badmouth her in front of the kids but I also dont want to pretend everything was fine. Honestly I'm wondering if he overheard something. Should I ask him what made him think of it?