It sounds like a conversation about this is a good idea. Have you read up on the S.E.T. communications technique? It might help here.
I'd suggest that you explain that for you it is a much bigger thing to lie about the past than to fail to live up to a commitment about the future.
Yes, I've read up on SET and I try to use it faithfully. I had a session with my T this morning, and he expressed concern over me not putting enough of myself into this discussion with my husband. My T agreed that I will have to be mindful of the fact that my H might dysregulate or turn this all around on me, but urged me not to be TOO careful in what I say. In other words, I have a right to be mad and let my husband know that.
So, in a way, I feel a bit torn: on one hand, I know that doing things the "right" way will most likely yield a better result. On the other hand, I agree with my T that I may be focusing too much on my husband's feelings and not enough my own. This is why you are all telling me that I have to be strong! (And of course, I completely agree).
My husband isn't going to be home for another week, so I still have some time to think about what I'd like to say. Based on all of the great feedback I've got here and from my T, I know that I must not be unwavering in my delivery, but also show empathy. It's clear that he doesn't feel comfortable telling me the truth, for what reason- I don't know, but whatever it is, I hope that he is willing to work on talking about it. Otherwise, I fear this will happen again.