I just recently proposed so I can feel little sympathy for her. Its a nerve wracking process to pick a ring, think about how to propose, etc. For her to know that he is proposing and still go ahead and cheat (and regardless of if they only got caught making out, she pretty much said she had slept with the guy while they were together: 'I made a mistake' a few months ago) Personally I think it wasn't even that harsh. The only harsh thing is that the whole world knows she's a cheater, but than really she deserves that considering.. just my 2 cents.
Maybe Eric will consider proposing, more likely tho he will continue enjoying his piece.