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When you're spending the major part of your life apart from the one you think you love, you just don't give yourself the means to develop real intimacies - sexual or otherwise - in a relationship. I think LW is just a fairly reserved and serious individual who has been raised with some expectations of something that doesn't always come naturally to everyone. Without enough time together - just the two of them - it's hard to find the kind of comfort and ease with a Significant Other that makes lovemaking a natural step. She's working against distance, time, cultural expectations, and the popular press!
It's hard for someone as logical and analytical as she sounds to make sense of this sex thing - either with herself or with someone else. Sex implies a complete loss of control, and an element of fear, tied in with all that religious training probably doesn't help her feel comfortable with it, either. The best advice is the bath - try it out a bit, but don't rush things and don't expect miracles immediately. Sex may be instinctual, yes, but there's a lot of it that's learned and practiced, and it sounds as if she hasn't really gotten comfortable with herself yet.