To want a child-free 20 mins?

[Trustisamust]

I have three children - 13, 10 and 9 months. The 10 yo just will not go to bed. He says staying upstairs on his own is making him anxious. He goes up at around 9pm but then is down within minutes. My baby is then up and on the boob from around 9.30 so both of them are around.
I then go up about 10pm as it's the only way middle child will settle.
AIBU to just want 20 mins of an evening to myself? To share 20 mins time with my fiancé? Or am I being selfish?

Yanbu at all. My elder child doesn’t go to bed at a reasonable time and I’ve got a small baby. My every waking moment contains a child.

He's 10, just tell him to go to bed. Unless he's in an upper turret by himself, he's being ridiculous.
What does he like doing? My 10 year old likes roblox. So my bed - no Roblox tomorrow.

You can only care well for them if you take care of yourself as well. However, I would try to figure out why your 10 year old is anxious. We have all had a very tough year. Would a night light help him? Or a sound machine (eg. waves)/ soft music? A hotty? Could you record yourself reading a story and play that every night to him after going to bed?