My Partner (20s m) and I (20s nb) have been dating for most of a year and today I'm struggling with a situation around sticking to agreed times.

We live ~2 hours apart and are currently each others only partners. This is also the first proper poly relationship for both of us. We have been poly the whole time but both lead busy lives so haven't been dating that much. I'm adding this cause I'm very aware I tend to get insecure around new dates etc. in part because it is all still new to me and I know this will probably get better with time and age.

Anyways since we live quite a bit apart he spends a lot of time at my place, he stayed here last night and is staying tonight, but has a date today with someone he's met once before. I'm already struggling a bit with him being at mine and using it as base for this date, but to be fair haven't spoken up about it as the time he's here is not really active date time but more so coworking and spending down time together. I spoke to him yesterday about wanting to know when he'd be back so that I can be emotionally prepared for the time he isn't around. This may sound stupid but I'm autistic and not knowing this kind of stuff stresses me out a lot, specifically not knowing start/end times. He said he'd be back at 6 pm, which is fine.

Then he also wasn't feeling great yesterday, so wasn't sure if he'd be able to make his date. He let her know this and she then asked to be notified by 9am if he could or couldn't make it. Not entirely sure how the communication around this went after that since it's not my conversation but he's a night owl and woke up this morning around 11, he was originally supposed to leave at 12:30 but then his date texted she was running late by about an hour and a half.

So, he left later to meet her and then texted me at around 4:30 that he'd be coming back an hour and a half later than originally planned. I am mad, as we've had some talks about sticking to an agreed time before and I really struggle when it's so (to me) short notice for a non emergency/out of control reason.

I feel like if he says he'll be back at 6, he should be back at 6, unless there's an emergency or something. His date running late (if because he didn't text her at 9 or not, I don't know) doesn't justify it for me. I think if he'd asked me before leaving if it would be okay if he came later I would've been fine but this just sent me into being unproductive and sad. In my opinion him or his date not sticking to plans should not affect our time together, even if it's just down time/coworking. Feeling very unsupported right now.

Any advice or words of wisdom are welcome, I have texted him my feelings and will talk to him later but I had to get it out to hopefully not just mope around until he's back.