What do you think if I want my partner to stick to what time they say they'll come home?
How do you feel when she is never on time?
I feel it is insulting to be late
You cannot expect someone to be at home on time all the time. Traffic is a thing or they could pick up food causing them to be late you sound paranoid.
I've never missed the bus and I can't be late because I am always on time.
You are really excellent at being on time. You are a perfectionist, but you really should be flexible when it comes to your partner because you don't know if there are unforeseeable circumstances. I am sure your partner is aware and is doing the best they can to be on time because no one likes to be late.