My ex and I have been broke up 5ish years and we get on reasonably ok. He has been dating someone for 6 months, on every occasion I've met her she refers to the ex as boyfriend - like she'll come in from work when I'm dropping off DD and say - "hi boyfriend!" or "thanks for washing up boyfriend"
I thought it was like a territorial thing, until DD asked why does gf calls him boyfriend and never uses his name?
And I don't think its a jealousy thing because I remember watching Gilmore Girls, in which one of the characters would always call her boyfriend - boyfriend and never use his name. And it use to really annoy me.
It really sets my teeth on edge. I wouldn't give a shit if she called him babe, sweetie etc.