Rambling is generally good, and I hope you had the chance to vent some of your pent up frustration by speaking out your thoughts and feelings on the matter.

As for the conflict being torn between your Master and your husband, I think there is a lot of further information that is needed to give you a fair response in what you should do.

First of all, you said that you wanted to save your marriage, but with the first two sessions with your husband being your Top you enjoyed it, but it lacked the passion, or rather lust, of your meetings with your Master. Part of the reason for that is because your relationship with your Master, in your mind, is forbidden, and that has an arousing factor to its own which your husband will not match because your relationship with him is not "forbidden". This already tips the scales in favor of your Master, who likely has more experience in the realm of bdsm and is likely to know you more intimately than your husband.

As for what you should choose to do in this situation, that requires a lot more information, a lot more serious discussion, and someone who knows you and your desires well to speak to a straight answer that is suited best for your wants and needs.

In the scenario provided, it sounds like neither is a good match, but together they meet your needs. If one is too far from a lifestyle that you need to live, and the other is too experienced to give you the deeper understanding and intimacy you desire, it seems almost like you need to find a third who can meet both needs equally. Obviously, the ideal world is not going to happen, so it depends on which needs you desire more, the environment or the dominance.

Best of luck on choosing.