My DH's brother and girlfriend loved my DD and always had time for her. They struggled to have a child but were blessed last year with a little girl. From the minute their DDwas born they make sly digs about my DD. refer to their child as 'the competition', mention how their DD has stolen my DD thunder. I've bit my tongue and walk out of rooms when stuff is said as I don't want to upset mother in law but it's now starting to really upset me. I have pulled them s few times in private but they play innocent and make out in being silly. What should I do?