Why would my ex suddenly ask if I’m seeing someone now?

Three years ago I went to the barber to cut my hair, everything was going smoothly until my ex shows up he saw me and started asking me questions along the lines of if I’m seeing someone and I’d so do I cheat? He then precedes to ask me for money and I told him no right when I was about to leave he looked real mad. so the question I’m asking is why do ex want to know who I’m in a relationship with?
Why would my ex suddenly ask if I’m seeing someone now?
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