NC'd for this.
Bit of background to avoid drip feed.
My BF and I have been close since our teenage years, godparents to each other's children's etc. We both work long hours and have busy families but we've both been there for each other when it mattered - bereavements etc.
Luckily our DHs are very fond of each other too and I view BF and BFDH as family. 10 years ago, my DH admitted to a long and protracted affair which devastated me and it took me a long long time to feel anywhere near mentally well. DH and I worked through it and are as happy as most married couples now.
Anyway, my BF has recently told me she is currently having an affair.
I know the man involved who is also married and he has 3 young children. It's been going on for a while and there wasn't any suggestion that they were planning to stop. Nor are they planning on splitting from their partners.
Obviously I was told in confidence but I'm now faced with seeing her DH who is very dear to me (and close to my DH) whilst knowing what's going on.
I know it's irrational but i feel let down and hurt that my lovely BF could spend nights in the past wiping my tears and calming my hysteria yet can go on (albeit a long time later) to do the same thing.
I feel betrayed but I think that is probably because it's reminded me of how it felt all those years ago.
Am I being irrational feeling like this? She is the kindest, loveliest person I know and I love her like a sister. This is totally out of character for her but I'm so upset that she's made me complicit in a situation I abhor.