Within relationships, it is not unusual for there to be a mismatch of sexual desire, interest and/or satisfaction. The key to correcting these issues is to find a compromise that suits and satisfies both of you.
It would be extremely premature and a monumental mistake to think that the only way to solve this problem is to separate. Separation would likely be a great loss to you and your children, especially from a man who you describe as “the best father I have ever seen, both emotionally and financially. He is also a very loving husband, attentive, appreciative, and affectionate.” Sex can be an important part of a relationship but the qualities you describe your husband as possessing are far more essential to a healthy and happy marriage. Many women would say that you are extremely lucky to have such a wonderful husband and father for your children.
To this point, you said that you have only “gently” hinted at this issue with him. You’re ready to end the relationship but you have barely spoken to him about it. You need to be more direct with him about how much of a problem this is for you. He needs to know. The fact that you have hardly mentioned this issue to him indicates that there may be a serious lack of communication in the relationship, at least with regard to this issue.
You should strongly consider marriage counseling. This could include you and your husband going to counseling together as a couple or separately for individual counseling with both of you seeing the same therapist (I would recommend the latter). Through marriage counseling you may find that this problem can be resolved fairly easily. A therapist can coach you on how to speak to your husband about this issue, teach you more effective ways to communicate and may help your husband overcome any issues he is facing regarding sex and intimacy.