First, define risky sexual behavior. I'm going to go with medically risky, since it tends to also include other categories, such as socially risky.
So, obviously it has an impact on your health. There's the risk of a STD, of pregnancy, and of hospitalization in general depending on what sexual activities you engage in (incorrectly).
There's an impact on your social life - it will affect who you hang out with, what your family thinks of you.
There's a potential impact on your professional life if your job or your clients discover what you've been doing.
There may also be legal ramifications if your risky sexual behavior happens to be illegal in the area you were doing them in.