My mum is in the middle of a divorce. We aren't close, speak maybe once a month or so. She was with my step dad for around 15 years, and I'm fairly close to him, we've got loads in common and talk a little more than I do to my mum (there are reasons for this, really valid reasons). I'm meeting his new girlfriend next month, at an event that we all share an interest in. Do I need to tell my mum that I'm meeting her? It feels slightly disloyal given the divorce but I don't have the most functional relationship with my mum, whereas my step dad has generally been supportive and kind to me.