Me And Partner Have Been Doing Unprotected Sex Since Last

Me and partner have been doing unprotected sex since last 3 years but never ejaculated inside her. She never had any contreceptive pill. Also she confessed that she had been doing unprotected sex since she was 17 years old with ex-bf and now she is 26. But she never got pregnent. Does this means she is infertile so cannot become pregnent. We are going to be married soon so can we get treament so that she can be pregent after treatment.