OK Dani, I don't want to burst your bubble here, but when MEN are having PA's then can get NICE to their spouses... at least in some cases... its not because they have grown up, its simply because they feel GUILTY.
I am worried you MAY be confusing GUILT with maturity. There's a huge difference between being attentive because you are secretly hurting someone, and actually manning-up to NOT hurt your spouse at all.
If he's still in contact with her after you take a full stand on NC then he's just been feeling guilty.... I hope its true growth, but I suspect it's merely guilt.