Johnny and Vanessa split up shortly after having Jack. It was hard at the time, but needed to be done.

And anyways, after he healed, he found you and was immediately smitten. But Vanessa was still hurting, and he didn't want to make it any harder by flaunting his relationship with you.

However, when things between you two got serious, he knew it was time to introduce you to the children, who of course were still young.