Andy Millin, 32, was walking with his boyfriend Cameron Stringer, 26, at the end of a night out on Saturday when they were attacked outside CC Blooms near the top of Leith Walk for holding hands.
Cameron was targeted first, but Andy says he stepped in to help him and was left with an injury that required stitches.
He shared images of his face following the incident which also saw his partner punched.
Writing on Facebook, Andy Claims the attack took place simply because they were holding hands.
Speaking to the Scottish Sun, hotel worker Andy said: “We’d been at a friends barbecue and went to CC Blooms for a few drinks. We left at about 3am and were on our way home.
“We crossed the road holding hands and there was a couple of guys behind us. One of them ran up and kicked Cameron in the back.
“He was about to attack him but my first instinct was to get him out of the way. I got punched and then I blacked out.
“I had a lot of blood so Cameron told me to sit down on the pavement, but then one of the guys ran back round and punched Cameron. His injuries weren’t bad, he just had a bit of a lump.
“We’re alright now but still a bit shaken.”
The pair have reported the incident to police but don’t have a good recollection of the men’s appearances other than that they spoke a foreign language.
A Police Scotland spokesperson said: “Police are investigating after two men were assaulted in the street in Edinburgh city centre in the early hours of Sunday morning 20th May.
“At around 2.45am the men, in their 20s and 30s, were kicked and punched on Union Street by two other men who ran off along Leith Walk.
“Officers are carrying out inquiries and this incident is being treated as a hate crime.
“Anyone with information should contact police on 101 quoting reference 1028 of Sunday 20th May or Crimestoppers anonymously on 0800 555 111.”