Lindsay Lohan and her new beau Calum Best broke out into a huge screaming match inside a New York City hotel on Monday night. According to about 900 different sources, Lindsay's pissed because Calum is cheating on her. An "onlooker" told the New York Post:

The "screamfest" started in the penthouse and ended up in the lobby. "Calum's clothes were torn, and after a few minutes, they got back into the elevator and went back to their room," said one onlooker.

Lohan seemed unfazed by reports of her British beau canoodling with another girl in the islands Friday night - but Best's raunchy behavior at Cipriani Downtown on Sunday might have sent her over the edge. Our spies saw Best "collecting numbers from all the models" every time Lohan's back was turned. (Source)

And this from the New York Daily News:

Late last week, a room-service staffer is said to have found Best with another woman when he asked that his minibar be restocked around 4 a.m.

According to our source, Best had his shirt off and the girl was on the bed when the urgent delivery of little booze bottles arrived. Best is said to have invited the room-service guy to grab a tip from a pile of cash, saying: "It's Lindsay's money. I don't care." (Source)

So Lindsay's been with this dude for only a few weeks now and he's already cheated on her approximately 37 times. Sounds like Calum has a future career as a gossip blogger ... heh heh heh *pops collar*