You know, sometimes spouses or the equivalent thereof are best friends, and other times they are lovers. They are multi-layered and complex relationships. People have different needs at different times. Couples with one person having a high libido, while the other a low libido experience the complexities often and learn to negotiate through the frustrations of not getting all their needs met allt he time. I would ask you to consider that while yours isn't a case of hl/ll conflict, it is multi-layered, so therefore, work through one layer at a time.
I have been twice divorced, and can attest to the conflicts of divorce. For you, your spouse, your kids. The first time, my husband was nice about it, but like you, I had married without thinking about what I was doing, and thought I could do better than
him. 
How selfish does that sound? So, I found another soulmate, who, unfortunately wasn't any better (worse, in fact,) and now I am on my 3rd soulmate. If I'd known in the beginning what I know now, I would have worked to keep the 1st soulmate, developed multiple layers of partnership. Relationships are about so much more than
just sex! The grass will always appear greener some distance away. Just like it's greener over a septic tank. Water what you have,
find and pick the flowers. And if it is so horrible, you can always do something about it later, but for your children's sakes, stay put and work on what you've got to make it the best it can be.