Who doesn't check their iud string?

So ive had the skyla iud for almost a year. I love it. Although during use i developed horrible hormonal cystic acne which we tried treating with topical treatments for the entire time. Now today we made the jump to try spironolactone. Which as some pf you may know it can cause defects to the male fetus. So i absolutely do not want to get pregnant on this drug. I never have checked my string. Sometimes my boyfriend says he feels it others he doesnt. I even went to my doctor once and she said i have a long vagina tmi i know but that i wouldn't be able to check it myself anyway. Should i just relax knowing i am on the most effective birth control there is? Just looking for advice thoughts and opinions.