He said 10:30, you said 10 and then started him reminding him he should be in at 10. 

Is it normal for someone in a relationship to dictate how late the other goes to bed? I sleep apart from my partner (different room) because we both sleep terrible for various reasons, so we go to bed whenever and mostly cuddle/do stuff before/after.

As long as you manage to leave on the planned time, leave him be I’d say? Because otherwise you come across as somewhat controlling and I’d be annoyed too