Simon Cowell on the verge of splitting from Terri Seymour

American Idol judge Simon Cowell is on the verge of splitting from his longterm girlfriend Terri Seymour, it has been claimed.

The pair, who have been dating for five years, have drifted increasingly apart, and friends blame Simon's obsession with work, his refusal to get married and his flirting with star-struck female fans on their troubles.

Their differences were apparent over Christmas and New Year when they holidayed in the exclusive Sandy Lane Hotel in Barbados and publicly argued about his stubborn refusal to commit himself any further to the relationship.

A source close to the pair said: "It really is make or break time. She loves Simon but he's the most stubborn man in the world to live with.

"He's always travelling the globe due to his work commitments and they are hardly ever in the same place at the same time.

"Terri's 33 now and really wants kids but Simon isn't interested. Every time she raises the question he changes the subject.

"Yes she has a great life and wants for nothing but Terri is a simple girl at heart who just wants to be a mum and settle down. No amount of money or fame can ever compensate for that."

Model Terri is close to Simon's 82-year-old mom Julie, and is often on the phone discussing her worries and frustrations.

The source added to Britain's Sunday People newspaper: "Julie tries to bend Simon's ear but he won't listen. Now Terri is planning a life without Simon. She feels like she is being taken for granted".

The music mogul -- who's worth an estimated $200m -- said recently: "I don't believe in marriage, certainly not in this business. The truth is that you get married and in a year or two they clean you out. It's just not going to work. The whole culture just puts you in a very weakened position."

The pair are both living in separate houses, Terri recently bought her own house in the Hollywood Hills for $4.6million; and Simon, 48, is in a rented property while he waits for builders to finish his new multi-million-dollar mansion in Beverly Hills.

Adds the source: "She is worn down by Simon's attitude towards their future life together.

"As for his new home, she has had no input on its interior design or choice of furnishings. Every single decision is made by Simon. It's as if it's his ultimate bachelor pad. Terri also feels upset and humiliated every time Simon mouths off about his unwillingness to get married or have kids in interviews. She thinks it shows a lack of respect towards her."

Another sore point for Terri is the way Cowell has become a target for fame-hungry girls in the US.

"Simon can make someone famous overnight like the singer Leona Lewis, and because of that woman are desperate to be with him," adds the source. "They follow him into the loo. They're shameless. But it really gets up Terri's nose. She hates it, because she feels like she's acting like a bodyguard all the time.

"Basically Simon loves the attention. Women swarm around him at parties even if Terri's in the same room.

"Simon does nothing to put them off. Can you imagine how that makes Terri feel? He doesn't realize how much he is hurting her by his actions.

"Seeing him out with other women just humiliates Terri. She tries to laugh it off but inside she is seething."

Terri has previously spoken about her frustrations over Cowell.

She said: "I've known his thoughts on marriage and babies from the beginning.

"He doesn't want kids, full stop...I would definitely love to have a baby in the future definitely." And asked if she'd dump Cowell in the future if he still refused to have kids or commit, Terri added tellingly: "I haven't allowed myself to think in that way yet.

"Maybe I will shortly.

"It's not something I am worrying about right now. Definitely in the next couple of years, I'd have thought."

Cowell's spokesman Max Clifford said: "I've spoken to Simon about this and he and Terri are absolutely fine. They're as happy as they've always been."