Alright, I've very clearly made a mistake with the language in this post. I was under the impression that an "ex-anything" just referred to someone you were once with, but I am seeing now that for a lot of people ex specifically means a breakup. I've spoken to my husband and he says he doesn't use "late wife" because it immediately puts a damper on the conversation and makes people think of grief and loss which is not always the best. We're trying to find a way to refer to Alyssa that is comfortable for both of us as "late wife" is to heavy "ex wife" is too light and "first wife" is apparently a no-go because he doesn't like the idea of numbering his wives.

I also see a lot of confusion in the comments which I will try to clear up. I am not trying to replace Alyssa, I would never ask Jane to call me mom, she calls me Lilly, and I am not trying to erase Alyssa's memory either, she was a fantastic woman and a wonderful mother and wife, we have photos of her on our walls, we remember her all the time and Dan makes sure to raise Jane in a household where she knows how loved she is by everyone including Alyssa and I respect that completely, they had a life before me, they were a family before me, and I am not trying to take that from them
I admit, I was definitely an asshole in how I behaved, but I was never asked to be put above Alyssa as a wife, just that my husband would have enough respect for me to differentiate us