My sister has been treated like crap by her boyfriend ( 18 years her junior) for the majority of their 4 year relationship. His behaviour at Xmas was spectacularly bad - disappeared for a week , came back and took their son to his parents for a week. They subsequently split up, she promised me that was definitely it and they would not be getting back together. And yet here we are lo and behold she is back with him , I'm so cross with her I literally have zero respect for her now and don't even want to speak to her. Really it has no baring on my life I'm just struggling to be friendly with someone who is a complete idiot basically ! Anyone been in a similar situation?