Is he being secretive? Is he busy on nights/times he said he'd be free? Is he hiding his mobile? Does he have 2 mobiles? Does he move to answer a text (IE get up and move away from you)?
No to all that, then you ain't got to worry. As those are all "signs" of someone up to no good.
I've called my fiancee the wrong name, and her mum mum.for months kept calling me by the name of my OHs first husband (they'd divorced thirty plus years ago). Names are so easy to get wrong.
Is you name similar in any way to the ex?
This is why most men (and yes I'm being generic) call their OHs babe, darling, dear, sexy, etc etc, it's because we're rubbish with names.
Especially as he's doing this after a hard night's work, and none of the above, then I'd leave it at pure tiredness.
Try making a joke of it.... Oi, I don't burn your dinner! Or whatever he said the ex did badly.