
For the dad to get upset when you accuse him of all sorts of nasty stuff is no surprise.
And if you have your man living in another house because of your anger then his "affair" is partly your own fault (if he even had an affair).
I doubt he was angry about you "finding out" because that is ridiculous.
It is far more likely that your baby's dad was angry that you accuse him based on some Internet search and random words from a website.
You really need to get your values back in order.
Defend the marriage and get back with your husband and then if there is any cheating it will not be over the Internet.
Try protecting your family unit by getting your baby's dad back before you ruin it all.