Dating is a minefield. One minute you're madly in love with someone, the next, you can't stand them; everything they do annoys you.
At one time or another, we've all had the dreaded 'ick'. But what is it and why does it come on all of a sudden to ruin a new relationship?
Speaking to the Independent, Lara Asprey, the founder of matchmaking organisation Asprey Introductions, said it's out of our control.
She said: "It all comes down to how we can form a preconceived notion of someone and establish in our psyche an identity before we know who they really are.
"We, therefore, build people up before they have had the chance to prove themselves and then get wholly disappointed."
Sally Sheldon is a lead neuroscientist at brain training app Peak.
She believes that the 'ick' is the manifestation of a person's 'inner critic', which she says holds people back from being truly happy.
She said: "When you start to feel your relationship is heating up, your brain tries to protect you.
"When our minds circulate fearful, critical, judgemental thoughts, our brains release stress hormones, such as cortisol. Why? Because our brain doesn't know the difference between an event that's actually happening and one that we are imagining.
"Our survival response (fight, flight, or freeze) overrides our logical brains, putting our system on guard. We then convince ourselves that we're going to get hurt by this person, and we convince ourselves we don't like them anymore."
And while some experts believe that we can overcome the 'ick', Asprey isn't so confident, claiming that it's impossible to change.
She added: "If you find yourself relating to this and developing 'the ick' then it's almost certain your 'situationship' will only go in one direction.
"You need to ask yourself if you are referring to an idealised image of what you want."
But how we choose to respond to the 'ick' is all on us, says Dr Becky Spelman, a psychologist and clinical director of Private Therapy Clinic.
She argues that it's vital a person takes responsibility for what they choose to do when they start to go off their new flame.
"You may suddenly be struggling with feelings of revulsion towards them, but they are still the same person you were attracted to until recently," said Sr Spelman.
"This is the most important thing to remember, so that you do not consciously or unconsciously attempt to place the blame for your subjective feelings of revulsion on their shoulders."