ual abuse,and now into a relationship,proplems.?

a couple i know ,the famale was ualy abused about age 9 by the stepfather.the stepfather was jailed.the stepfather got back with the mother of the child and are still together,it never happened again ,the victim now years on is in a relationship for three years,engaged.and living with her boyfriend.the relationship has never been a ual one maybe for the first few months,this abuse is never mentioned and the fact that the stepfather is still with her mother may contribute to the problems.its like what is done is done so keep it all hush hush i have suggested maybe seing some councillor like relate or something,theres other problems aswell,im worried for them they do love each other but are like a brother sister relationship.they have both got respectable jobs but lately when she goes out she has been doing drugs.iam so worried any suggestions please emma xxx