I be went my fiance going on two year's still nothing been trying not sure what im doing wrong i know i can have them to have a beautiful princess that's two

Is it me I been in relationship almost two years my fiance been in my daughter life since she was two months old treats her like his own. I want to complete my family by having his child been trying nothing yet we lost our baby about eight months ago do to being pregnant in my tubes. Now I feel like something is wrong with me but were still trying