She rarely e-mails, the Sunday brunch ritual is dead and - most chilling of all - she's started speaking in first-person plural: " We can't wait for the holidays";" We hate that restaurant."
Your friend has a new love interest who seems to have replaced you, you poor thing. At least you're not alone: Chances are the new significant other has also supplanted someone else.
New research completed at the University of Oxford suggests that on average, people shed one friend and one family member from their inner circles when they start a new romantic relationship.
Robin Dunbar, the British anthropologist who has famously studied the science behind online social networks, and post-doctoral fellow Max Burton-Chellew surveyed people 18 to 69 online about their friends and lovers.
The online survey's participants - 428 females and 112 males - were asked to list all the people they felt they could turn to in a severe emotional or financial crisis. They were also asked how long they'd been involved in their personal relationships.
While the singletons listed an average of five people in their support network, those in relationships only had four (including romantic partners). "There's a kind of isolation effect occurring when a new relationship forms," Dr. Burton-Chellew explains. "They're turning inwards instead of outwards."
He points out that this can put a lot of pressure on people because suddenly, as boyfriend or girlfriend, the individual is expected to offer the same amount of support that two people once brought to the table.
Jessica Booth, a 22-year-old web writer in Long Island, N.Y., says she's noticed all the women she's close with ditch friends at the start of relationships. The most stinging instance was a friend she's known since she was 14.
The woman she saw almost every day became distant a year and a half ago when she found a new boyfriend.
"One day they went out on a date and the next day she was gone. It was right away," Ms. Booth says. "I feel like she just needed somebody around her all the time and once she had him she didn't really need us around."
Instead of just shedding two close relationships, as was the case with most participants in the Oxford survey, Ms. Booth says her friend cut ties with four of her female pals.
One issue rarely considered by deserters is what happens in the event of a break-up.
"You could sort of put all your eggs in one basket and end up isolated," he says.