I posted about this a while ago , in a slightly different way.
My BF's marriage has gone tits up, and reached crunch point. They are both to blame, but she only sees fault in his behaviour. TBH what has happened was an accident waiting to happen, and I did try to warn her before, but she wouldn't have it. She's asking me for advice but I know that if I really spoke my mind she'd find it hard to take and it would threaten our 30 year friendship. They live apart for most of the year due to his job, (she refused to relocate with him) and he admits that someone else has shown some interest in him, although he says nothing has happened, and he needs to "think" about where they go from here.
I feel her behaviour inthe past has been very unfair on him, but if I was to say this she would be livid. How can I avoid speaking my mind when she insists on knowing how I see it all?