Have you heard of the "Let Them theory", the viral self-help trend popularised by American motivational speaker Mel Robbins? The mantra, according to Robbins, can help you let go of situations you can't control.  But what do psychologists say about what happens if the theory is applied to our actual relationships and life goals? Clinical psychologist Dr Jacqueline Baulch weighs in. And, aunties, comedian Reuben Kaye and journalist Denise Eriksen, advise on what to do when your no-strings-attached hook-up is getting you all tied up.