Did you mean to say "WOULD have been part of the equation"?
If the child WAS sure to be his, the mom could have instantly relieved his suspicions by simply saying "Of course it's yours, and to prove it we will have a DNA test done tomorrow morning".
If she had instead said "Too late, sucka! You have acknowledged paternity, so you are stuck with child support for the next 18 years, and there's NOTHING you can do about it!", then his blowing her away is understandable.
His blowing her away was not understandable under any circumstances, and YOU don’t even know what happened.
Are we to believe this guy wasn’t on the make with other women?? PUHLEASE. He was with another woman that very night, before “blowing her away”.