I suffer from this urge as well, and it has been an excruciatingly difficult habit to break. However, it's important to understand that there is a very thin line between being humble in a healthy way and being self-deprecating in a damaging way. The first is attractive, the second not so much. You don't need to point out your flaws to prove that you aren't vain. Any partner who is genuine in their attraction to you isn't going to want, need, or require an apology for yourself in advance to your clothes coming off. Period. Like I said, I still struggle with this myself, but I'm learning and I'm determined to understand it. My partner has taught me a very important lesson: perfection is not a prerequisite for sex appeal. He has put in consistent hard work in helping me harness the power of that knowledge and, honestly, it's working. If you're interested in more conversation on this, I'm sure he'd be happy to share his perspective on it as well. It's a struggle of mine that has had heavy impact on our relationship and as such I think it's fair to say that we both have experience in dealing with this from both sides of the coin.