Should I cancel dinner?

Sophie Adams says:
I made dinner plans with my boyfriend of 1 month for tonight. He sent me a text around lunch saying he's having a crazy busy day and he has no idea when he's going to get off work and he's been there since 6am. He didn't say anything about dinner but I'm reading into it.
I responded to tell him to hang in there and if he needs to cancel dinner plans, I'll understand. His response was that he'll keep me posted. Part of me was hoping he'd say "no way!!!".
Should I have given him that out, or should I have left it up to him to make that decision?
Historically, I fear rejection and if it's my idea, then I'm not being rejected but if he does then I am. Should I be giving him that out? 

You did exactly the right thing. However, if it becomes a regular thing, you will have to decide whether you're going to accept that. It's about flexibility. You understand sometimes work is hectic and he has to understand you must come first at least some of the time. If he can't be flexible, you are choosing to accept to be second to his career. All this remains to be seen. For now, respect to you for being understanding.