What do i need to tell my fiance about my future health? i have congenital heart defects.

Depends:: Your prognosis depends on the type of heart defect you have and the degree to which it was corrected. Since you are likely to have a scar on your chest if you had surgical repair, i suggest telling sooner rather than later.

Depends on what type: Congenital heart disease comes in many flavors from minor to serious heart problems. Discuss the specifics of your disease with your heart doctor, typical conversations with a loved on would include discussions of your ongoing health including possibly needing further surgery, and your plans for contraception or children, which you may be advised against having. See http://www.Achaheart.Org.