What is the magic number? How many dates do two people have to go on before they are dating? And, if they are dating, does that mean they are in a relationship? Are they together, just the two of them, exclusively? How much time has to pass before they are?

One day last week, at Waterstones, I overhear something that reminds me of this blurred line. I am there to work, in the café, but I have rushed through town and crashed down at the only free table to catch my breath, so it takes a few minutes before I even take the books from my bag, and I find myself tuned in to the conversation of the people next to me.

From what I gather, one of the two girls, with a fuzzy sheep jacket and ginger hair piled up on top of her head, has been dumped. The man in question has just told her that he doesn’t want to take anything further. She doesn’t call it ‘dumped’ though, because she doesn’t really know where she stood with this guy to begin with. She knows that they weren’t in a relationship, that she was never his ‘girlfriend’, but she is also sure that she was certainly more than just his friend during the three months they spent ‘seeing each other’. She pauses once she has finished recounting what happened, and then admits quietly that, while it wasn’t quite a breakup, she is hurt.

“Several weeks in, some people are still  juggling a handful of people at once. After the same period, others might be living together, or even married”

The problem is that there is no relationship ruler. There is no gold standard, no measure by which we can judge whether we are in or out. In this world of dating apps and casual sex, it has become the norm that until it is explicitly established that two people are ‘exclusive’ they have free rein to date whoever they like. Several weeks in, some people are still spreading themselves thinly, juggling a handful of people at once. After the same period, others might be living together, or even married. This is unlikely, of course, an exceptional case, but is perfectly possible. There is no one length of time after which two people become one couple.

The friend, whose face I can’t see, but whose hair is black and shiny and reaches all the way down to her waist, apologises. She can do nothing to help, but she understands the feeling of what it is like to lose something you never really had to begin with. I think we all do. This is a universal sadness, the kind when you feel like you have no right to be sad at all.

Does sleeping with somebody count as a major milestone, I wonder, as the pair carry on discussing the dilemma. Is that what’s important? If you have sex on the fourth date, is that when the relationship becomes, well, a relationship? Or is it meeting the family? Surely not. Surely that comes afterwards. Is it when you stay over for the first time? It’s quite easy to remain unattached when you’re seeing them for only a couple of hours a week, leaving their house with your hair tied up and your knickers on back to front, but at the point where you stay, at the point where you’re comfortable enough waking up next to them and eating Shreddies in your pyjamas together — surely this is significant? Surely this is a sign that you are sliding into something serious?

“The grey area in the middle — that’s where most of us find ourselves”

The grey area in the middle — that’s where most of us find ourselves. It’s rarely obvious. We meet somebody we like. In a bar. At work. A friend of friend. We go out with them a few more times. We laugh at their jokes. We smile at their messages. We look forward to the next time we get to spend time with them as soon as we say goodbye. And we wait for the day when suddenly it becomes apparent that we’ve accidentally tripped and fallen into a relationship, without any real reassurance that this day will come at all.

I don’t think I’m alone in wishing that things were easier. Aren’t all of us casual daters a little bit frightened that we might bump into the person we are ‘seeing’ in town, ‘seeing’ someone else? I don’t want to embarrass myself, to ask for too much too early, but at the same time I don’t want to reserve myself for somebody who hasn’t reserved themselves for me.

As I sit there, in Waterstones, staring at the blank document I have managed to open on my laptop, I realise the only way out of this dilemma is to get over the fear of labels we all seem to have. By never committing, by refusing to define the relationships we find ourselves in, we are absolving ourselves of responsibility. If we are not in, then we don’t have to find an out, and there never has to be the difficult breakup conversation.

There may not be a relationship ruler, but to let ourselves be vulnerable in front of the people we are attached to, admitting that we like them and want to be exclusive, that we want to put labels on things — this is possibly the biggest milestone of all. If you have what it takes to tell the one person you want to date that you want to only date them, you’ve reached the turning point. Sure, there’s a risk the other person might not have reached the same point, but at least you know where you stand. At least you have reasserted your right to feel hurt, instead of pretending that this important thing, this person you care about, can walk away and you will feel nothing.