Ok, so your girlfriend has told you that she isn't willing to minimise the risk of pregnancy and has also said she is likely to continue any pregnancy that occurs. Now you have to decide what your response to that will be. Will you stay with her knowing that she isn't minimising the risk and will probably continue a pregnancy, regardless of paternity or will you decide that you aren't willing to take the risk of heavy involvement in the upbringing of another child.
I'd personally be concerned if my partner wasn't minimising the risk of pregnancy with other people. If he chose to do that, though, and informed me about it, he wouldn't be doing anything wrong. He's just making the choices that he thinks are best for him.