The researchers, after asked people about their inner core of friendships, found the core, which numbers about five people, dropped by two as a new lover came to dominate daily life.
"People who are in romantic relationships - instead of having the typical five [individuals] on average, they only have three in that circle," explained Robin Dunbar, a professor of evolutionary anthropology at Oxford.
In our life we have different kind of friends: there are people who we see at least once a week; people we go to at moments of crisis, people we see about once a month - the "sympathy group". They are all the people who, if they died tomorrow, we would miss and be upset about. The result of the research confirms that the intimacy of a relationship - your emotional engagement with it - correlates very tightly with the frequency of your interactions with those individuals.
If we don't see people, the emotional engagement starts to drop off, and quickly because our attention is so wholly focussed on your romantic partner that you just don't get to see the other folks you have a lot to do with, and therefore some of those relationships just start to deteriorate.