I feel horrible!!

Ashlee
So in February I started dating a guy I was going to school with! In early May we went to a party and my friends and I got extremely drunk and it slipped out of my best friends drunken words that she fancied him that whole time and it explained why my other friend was so negative about us being a 'thing' as everyone calls it. However my best friend is now the reason why my boyfriend and I are the way we are!! Should I feel guilty? Because I do and the more she hangs out with us the worse I tend to feel! I know it's been so long but it's all starting to creep up on me!!