But when Miss Ross asked a waitress for one for her girlfriend, she was told she could not have one because “lesbians aren’t real couples”.
The two said they were “disgusted” and Miss Simpson said the treatment left them feeling like “lower class citizens”.
She said: “It isn’t the rose, I have a dozen of them at home, it is the principle. This is the 21st century and we don’t deserve to be treated like that.
“I’d have thought that if they’d assumed we were straight they might have offered us roses for being single on Valentine’s night.
“But instead they just offered us discrimination and made us feel like lower class citizens.”
The pair, from Newark, Lincolnshire, have been in a relationship for four months and complained to the restaurant, sending three emails and a letter, and making a phone call before receiving an apology.
“Maybe they didn’t realise how offensive they were being but in this day and age they should. It was disgusting and it ruined our Valentine’s night. I will never go there again,” Miss Ross said.
“We don’t want to be compensated, just to receive a sincere apology.”
In a letter, Keith Gee, operations manager at the American-style diner, said the business took a “strong stance” on homophobia.
It said: “This is the first time we have ever had a sexuality complaint within our last 24 years in business from either guests or staff.
“On behalf of the company please accept my sincere apologies and I hope this will not deter you from dining with us in the future.”
He added: “We pride ourselves on trying to give every guest the very best experience possible when they dine at Damon’s.”
Mr Gee said staff and managers working that night had been interviewed over the complaint but so far no one had admitted making the remark.