The Girl Code or Do the Right Thing?

Yoe has been friends with sarah for around two years. She is currently in a long term relationship with a boy call him bryan. Over this time of knowing sarah, we became super close and incorporated our boy friends in our plans frequently for double dates, et cetera. Jo because of this, i, along with all the girl group, have become friends with b Bryan. And all our boy friends have also welcomed him with open arms. But over the last few months, sarah and i have noticeably drifted due to some differences in personalities. Do i pull her aside and tell her my feelings about her behaviour? Or do i sit back and keep quiet and stress to