Genital warts came back after 5 yrs.?!?

I had a genital wart 6 yrs. ago. I used Aldara cream to get rid of it. 8 mo. later I had another wart show up (diff. location) and I, again, used Aldara cream to get rid of it. The second one took a little while (12 weeks opposed to the 4 weeks it took for the first one to disappear), but it eventually went away. 5 years later the second (more stubborn one) has come back. Is this normal? I thought once they were gone for a few years they seldom came back. Please help. Serious answers only, please.