The natural reaction is, "Jaaays, isn't that lovely, he could've stuck around for her birthday, like," but it wasn't all his fault. He HAD to go partying with Orlando Boom because he had to be in NYC due to work commitments.

People Magazine has more "details": "Jennifer Aniston and Justin Theroux weren’t together for her 45th birthday Tuesday, but it appears that she was on her fiancé’s mind. Theroux, 42, was spotted by photographers in Manhattan’s West Village Tuesday at the boutique perfumery Aedes de Venusta, where he presumably picked up a gift for the birthday girl. That night, he attended a party at the Deth Killers store opening elsewhere in the city. 'Justin was very sweet,' a rep for the opening tells PEOPLE. 'Smiled for pictures, and was friendly to staff in the shop. Took selfies with partygoers alongside Orlando [Bloom].' Theroux arrived at the bash around 7:30, according to the rep, after spending the day filming his new show, The Leftovers. 'Justin was upbeat and laughing in the shop with Orlando, as he tried on different hats, which he ended up wearing out at the end of the night,' says the rep. Back in Los Angeles, Aniston was spotted celebrating her birthday with friends at SoHo House Tuesday in West Hollywood."

So the real person at fault here is Jennifer; apparently she wasn't working at all. She just wanted to stay in L.A. In fairness, who could blame her... New York looks only brassers at the minute. That or she's too far gone in her "pregnancy" to fly.

We'll leave it to Celebitchy to come across with their two cents on the situation: "If Justin and Jennifer really are on the rocks, I have an admission, and it’s something that few Brangeloonies will ever admit: I feel sorry for Jennifer a little bit in this situation. I think Justin got with her because she had money and a big name and a big profile and lots of connections, and he used her and got what he wanted from her professionally, and now he’s acting like he doesn’t give a s—t. And that sucks. He seems like such a douchebag."

What they said.