Actually, since there are children involved, I'm with you. And to answer Znufri from B2...
The reason he only told her "now" was because he couldn't carry the guilt any more. It was a purely selfish move on his part. After 7 years, he didn't do it to be honest or in the interest of full disclosure, he just couldn't stand owning it any more and told her so he could feel absolved of wrongdoing. He didn't consider her feelings in the least. Normally I'm for total honesty, but after all this time, the only thing telling her was going to do was hurt her.
So now, he feels like there's a big weight off his shoulders and she's devastated. What a prick.