Wow, I really liked this! I'm surprised because it contained infidelity which isn't my favorite topic. But you wrote it in a way that seemed appropriate and logical for the characters involved. The depth of the conversations Snape had with himself and with the other people and portraits also made sense.
I was very glad that Harry and Snape finally got together in the end, even though it was only after death they found happiness with each other for however much time they had.