If the soul to soul part's already there, the rest will fall into place by itself.
Boy, I have had a number of loving relationships and many sexual partners, and I just don't buy into this theory at all. I think pre-marital inexperience has led to many, many divorces on the part of baby boomers and others, and I know I have been in love with women whose relative lack of sex drive ended our relationships.
I know when I am dating someone sexually inexperienced, it is near-impossible to bring her up to speed, so to speak, and I think the chicken-and-egg theory is at work there. A woman (or, I suppose, a man, from his partner's perspective) who is fundamentally not that interested in sex (and who, as such, has had very few partners) ends up being, for lack of a better phrase, a dull lay. Tough to keep an interesting relationship alive with such a person. I frankly prefer a woman with experience, who enjoys sex.