From Harry and Sally to Rachel and Ross, the relationships that have dominated our screens have been those of the romantic heterosexual kind – and good luck trying to take any useful life-lessons from them. Much as you may have shed a tear of joy when Meg Ryan finally crossed paths with Tom Hanks at the top of the Empire State Building in Sleepless in Seattle, here in the boring old real world, chasing a guy you've written to, via his kid, across the country on Valentine's Day will more likely lead to a restraining order than it a happily ever after.

Hollywood had been mis-educating us on romance for nearly a century, but what about some of the other most important, but hard-to-navigate relationships in our lives; those we have with our best friends?

Sex and the City may have been too busy banging on about blokes to allow us any insight into the dynamic that kept a friendship between four women so strong (probably because IRL, their incongruous paths would not have crossed) but a new wave of female-friendship led fictions, including Lena Dunham's much discussed Girls, and Frances Ha, a new film from Noah Baumbach, co-written with, and starring Greta Gerwig, out on 26 July, offer a much more honest portrayal of these fraught but life-affirming friendships from which we can actually learn a thing or two.

Frances Ha's opening scenes tell a familiar tale – two girls, Sophie, played by Mickey Sumner, and Gerwig's Frances, who have met at college live in sweet synchronicity, like a 'lesbian couple who don't have sex', lighting each other's cigarettes, falling asleep under the glare of Netflix together, and sharing the same seemingly innocuous reasons to dump someone, 'he looks like the kind of guy who would say “take a leak”'.

Indeed, the subsequent fall-out when Sophie, who is doing well with her job in publishing, decides to move in with another friend in Tribeca, somewhere Frances, a struggling dancer could never afford, starts dating a 'take a leak' guy, and demotes Frances to the position of 'three-hour brunch friend', is all too familiar as well.

In my early twenties, I, and the close friends I lived with, revelled in the joys of the pseudo-sorority we'd created: sharing clothes, drinking the cheapest cider we could afford from Champagne glasses and bitching about the internships or underpaid temp jobs 22-year-olds tend to find themselves in. But when one of us landed a dream-job, and another was still struggling through her final year of university, the rest of us occupying various stages in between, to my surprise, the cracks in what we thought was an unbreakable friendship group began to appear.

Once there was a spat over something as trivial as what the necessary frequency to buy cheese was, which ended with my friend saying 'it's not my fault I earn more money than you'. Needless to say, we all bought our own cheese, of various expense and whenever we felt it was necessary, after that.

Similarly, at the close of series one of Girls, when tensions between Marnie and Hannah, finally reach tipping point and they fight over which one of them is the 'wound' in their friendship, it's clear to the audience that neither of them is infectious, but like Frances and Sophie in Frances Ha, it's the new incongruity of their achievement and attitudes towards life as they've moved through their tumultuous twenties, that has fractured the seemingly solid bond they once had. It's all very well being peas in a pod initially, but at some point, the pod will always burst.

When two people in a romantic relationship find themselves on different trajectories, they split up, move on and seek someone who's more relevant to their lives at this time. But to interchange old friends at every new juncture would mean missing out on some of the most valuable relationships life can offer us. Nothing beats being able to share a piece you've had published with a person who knows you wrote a choice selection of lyrics from Jagged Little Pill across your school diary, or to watch someone whose hair you once dyed pink get married, regardless of any arguments you may have had about cheddar - of the fromage and the fiscal variety.

The at times rocky relationship that plays out between Frances and Sophie in Frances Ha however, can teach us how to hang onto our close friends, regardless of what life throws at us.

For them, and for me, it takes accepting that independence from each other, is essential. Throughout the film Frances tells people that her and Sophie are 'the same person but with different hair', but it's only when they acknowledge that they have become very different people – Sophie living half way across the world dealing with very adult issues of unwanted pregnancy and romantic rifts, and Frances, who at one point tells her dance teacher that she 'has trouble leaving places', still trapped in her adolescent ways of flitting from flat to flat and struggling at her creative profession, that they are able to relinquish the closeness they once shared. They accept the fact that they will 'tell stories of what happened at the deli' to someone else, and become able to respect each other as individuals and thus maintain their friendship.

When, at the end of the film, the two vow not to re-create their once claustrophobic circumstance, but get 'apartments in the same neighbourhood', and we see their now separate lives come together, as Sophie, with her husband, shows her support at Frances' dance show, we're left in no doubt that their friendship is as strong as ever.

The group that I once found myself intertwined in has too gone its separate ways, each of us living in different areas of London that we have individually found an affinity with, or in one case, a different country entirely, and we have never been better friends for it, meeting up often and appreciating the very different nuances of each other's personalities and lives, rather than attempting to function as one large unit.

It doesn't just take the fact that Mickey Sumner, who plays Sophie in Frances Ha is Sting's daughter, to work out that the moral of the story, one that we should all learn to live by if we want to make our friendships last, is, 'if you love somebody, set them free'.