OP you've been with your partner 18 months!
If he didn't find you attractive, even the best sex wouldn't have kept him with you for that length of time.
If the truth be known I bet most couples start off without a host of fireworks exploding. The attractiveness of a person is made up of many things.
Lots of couples start out thinking that the person isn't drop dead gorgeous, but they see how things pan out. As they get to know each other, sincere feelings develop. There's some cases where the most stunning of people turn out to be absolute horrors personality wise.
Drunken times can cause upset, but your partner didn't say you were a "dog" now did he? Let's be honest here.
He said you weren't like your photos and he saw you again on the off chance he'd get lucky. None of that is unusual. Most people differ from photos if they've met online. Some may have worn more make-up, used photos they'd had taken at an event where they've really pushed the boat out like at parties, nights out etc.
He's said he's sorry, and he's obviously now realised he's got to curb the comments he makes whilst drunk. On the flip side of that though, he's honest, and he's probably voiced what many partners really don't. He probably thought you'd laugh and say "you cheeky sod"
To throw away 18 months seems silly. He'll only apologise for so long though, so either see him and tell him it's over, or discuss the matter and move on.