I know, we should have known 4 months back that the sister would start dating someone a month later with a birthday on the same day as our wedding. If only it was possible for someone to attend a wedding in the morning and have a party in the night we wouldn't have this conundrum..oh wait there's a good 8 hours left from our wedding time till 8pm!
So she's only been with him 3 months.
Your lass must be a reet black sheep for the whole family to do this. Or maybe they don't like your family/mates