The fire has gone out for Ellen DeGeneres and her lesbian flame, former “L.A. Firefighters” star Alexandra Hedison — and friends say it was battles over booze that put an end to the relationship!

The couple split up just weeks after the comedienne set up housekeeping with AA member Alexandra at the new home she bought in Beverly Hills.

Their on-again, off-again romance — already under pressure as Alex tried to cope with her girlfriend’s controlling ways just couldn’t survive the disagreements over Ellen’s drinking, even in moderate amounts.

“Ellen and Alex tried to make things work but they came to realize that they were just too different from one another,” said a source close to the couple, who began their love affair back in October 2000.

“Some of the biggest battles were over booze. Alex is a teetotaler who’s been going to AA meetings regularly for 41¼2 years now. Ellen often enjoys kicking back at home after a hard day’s work with a couple of glasses of wine.

“It got to be a real sore point between them. Alex constantly fought the temptation to fall back into drinking.”

For Alex, an ex-actress who has been pursuing a new career as a photographer, living with Ellen was enough of a pressure cooker without the struggles over booze. As the sitcom star’s girlfriend, she was expected to be constantly available for her lover — and to do things Ellen’s way, friends say.

“Alex felt suffocated by Ellen,” a friend of Ellen told The ENQUIRER. “Ellen is so busy with her series, career and just being famous, that her girlfriends usually have to drop everything to be with her. That was a big problem for Alex.”

What’s more, after the couple moved into Ellen’s new Beverly Hills home, it became obvious they weren’t equal partners in the relationship.

“Ellen made it clear to Alex that it was her house — and her rules” the source said. “That really rankled Alex.”

Tensions between the lovers were aggravated by Ellen’s intense mood swings.

“There are two Ellens — she’s like Dr. Jekyll and Ms. Hyde,” Ellen’s friend said.

“There’s the ‘poor-me, nobody-in-Hollywood-likes-me-anymore Ellen’ and then there’s the ‘boastful-top-of-the-world Ellen’ like after she came off of her well-received Emmy broadcast.

“If you’re with Ellen there’s a lot of stuff to deal with. It’s not easy being Ellen’s girlfriend.”

Ellen and Alex broke up and reconciled so many times that friends didn’t know what to make of their relationship. Then two weeks ago, the end finally came.

“They were at the Il Sole restaurant in West Hollywood,” said the friend. “They talked intensely for two hours, and then Ellen said, ‘Let’s face it, you can’t love me the way I want to be loved, and I can’t love you the way you need to be loved.’

“Alex agreed, saying, ‘You’re right. I love you, but I think we’re better off as friends.’

“After that last dinner together, Ellen called friends and told them, ‘This time it’s definitely over between us.’

“But Alex was actually good for Ellen after what she went through with her very public breakup with Anne Heche. At least Alex didn’t leave her for a man. And it gave Ellen hope that there are women out there who want to be with her for who she is and not because she’s in the spotlight.

“Once again, Ellen is officially single and looking forward to dating again!”