Losing hope

Well I am 27 and have no children. I have been trying for a while now. I am divorced me and the ex husband tried for many years.... I have found someone and we are to get married here soon. I just don't know if I can go through the heart ache again of seeing all the negative test... I want a baby more than anything. My boyfriend has a little girl and I have took on the mother roll in her life. So in away I have a child but I still want to have my own.