OP you see what happened, but are you at a stage to take it in and do anything?
I saw my ex finding excuses to be out, going to the gym more, hobby taking more time, texting friends constantly with a strange smile on his face, no interest in us unless putting me down, little interest in DC.
I saw it, but I couldn't acknowledge it. It was so obvious I told myself he was pretending to have an affair to be mean and controlling he was narcissistic anyhow . I knew her name too, he hesistated in a list of names and I saw his body language and still ignored it.
It is ok to take things slowly but, as precaution if things suddenly change, check you have records of ALL assets now.
One way to do this is to talk about an expensive holiday/home improvement and get figures together and write the savings you know about down, then say you wonder if it's high, but what about the rainy day/children's funds?
Also check you have access to funds now as solicitors are expensive.