I'm not sure of the "first time." He lied a whopper 3 months into our M, but I don't think that's what you're referring to. I would say (sadly) that two years into our M, I was already feeling like I made a huge mistake, that I chose incorrectly. Part of that was that I married a man with 4 children who put them before me from the very beginning. I used to think it would get better once the kids were off on their own, but it didn't take long to realize that they were just a symptom of the problem, and the problem lay with H.
So I guess I would try to answer your question by saying the disillusionment started pretty early on, and was reinforced pretty regularly over time. But I'm not sure that really matters. There's no going back. This is today and this is where I am. I know who/what H is. I'm not expecting him to change. I just don't know how to wrap my head around the idea of creating a healthy M with all the factors I have to incorporate into the R (eg. lying, loyalty first to kids, etc.) I've seen similar struggles here on a number of other posts. It's discouraging. I wish it was as simple as just acting as-if, but that doesn't seem to be a solution.