Easy for him to apologise now that she's dead and he can't be tested to prove himself by standing up for you over her, perhaps you may feel; and that's true. Seems to me that you feel deep resentment for this, and understandably so. His position will probably have seemed lose-lose to him, torn between the two women he loves most; and with her not having long to live he felt he should stand by her. But to your detriment of mind; and while an apology will not cover it, one must ask, really, what else can he offer? The past cannot be undone; but nor can your feelings about it. It is surely a good start to sit him down and explain to him fully, absolutely and completely the extent of your feelings. It IS OK to not be able to forgive someone for something in the past; it is destructive, but it is OK. He can only try to make it up to you in other ways that are future, and above all to reassure you, and show you, that you ARE his Number One - which seems to be the issue here. You two must present a united front and he must understand this. Wishing you all the best in the New Year and I hope that you can leave this darkness behind or at least minimise to yourself some elements of the past for the sake of the future.