If you are applying for divorce based on 1 year’s separation, you and your spouse can start living together again for up to 90 days in a row if you are trying to get back together. This will not affect the 1 year separation period. This is called trying to ‘reconcile.’
If you still decide to get divorced before the 90 days are up, your divorce can go ahead as if you had never moved back in together. However, if you get back together for more than 90 days in a row before deciding to proceed with your divorce, you will have to start counting your 1 year separation period over again.