Lose the friend. She's not much of a friend anyway. JMHO
As for the cards etc. I think he DID love you honestly and truly at the time. It is the MLC thing for sure. For our 25th my ex gave me a card "For the most wonderful 25 years. Can't wait for the next 25". He was already having the affair, bought HER jewellery for our anniversary and moved out the next month.
Burn them. I think that's the only way to get past it. And it is true GRIEF. In order to grieve and move on - sometimes we have to feel the pain. And mourn some more.
