"it's complicated"?

An ex reached out to me over insta dm. I responded and we talked for a little until I said "I guess you're not still seeing anyone". He said "Yeah, that's a whole complicated thing".

I then said " What does that mean" and he responded 16 hours later " it means people are complicated".

Is he still with her or what? What do I even say to that for clarification?
"it's complicated"?
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