It only happened once because your parents didn't allow it to happen again, good for them! He would do it again, I've never heard of someone who told me "my boyfriend hit me, but he never has again" Take a look at statistics as well, they defend my point of view. Also, did you know that children growing up in a house where abuse is present are 3x more likely to abuse someone else? This great guy could not only screw up your life and your child's, but someone else's as well. It's a vicious pattern that doesn't stop. I suggest you do get some help dealing with this, you have a child to live for, so pick yourself up and start living your life for your kid if you won't do it for yourself.