Of course it is too difficult for me to tell, but something about what you are saying is prompting me to offer an alternative explanation for what you are experiencing. Yes, it sounds like a depression, and I understand your concern about culture and not wanting to hurt a good man. But there are a few things you’re said that make me wonder if there is a self-defeating element to the depression. In other words, are things too good for you to accept?
You describe your good husband as wonderful, carefree and positive and your engagement and marriage as happy. You noted your reuniting was spiritual and fulfilling. Then, later, you say you are starting to have “self-deprecating thoughts about having put myself in this situation.” I realize I am taking this out of context, but you may be telling something that is closer to what is going on. The person you are describing as a mate seems to be a person worth being with, you have earned a Ph.D. at a very early age, and you are gainfully employed. In other words, there are many good things around you to be grateful for and happy about, but they do not seem to affect you. What I am suggesting is that your doubts may not be the concerns you did not honor. They may have been the seeds you planted in case you were feeling too good.
You also state in the beginning: “Because I come from a culture in which marriage and community are important, I am torn between that part of myself and the part that is immersed in a greater individualistic culture that values personal happiness and fulfillment.”
You state this as if they were opposites, as if they are at odds with one another. They need not be, but for some reason you have them as one or the other.
The possibility is that you are pulling out of a situation that is good. Why this is happening is unclear. Perhaps you feel unworthy. Perhaps it is the cultural value clash. But whatever is behind it may be more of a sabotage feeding the depression than the other way around. We tend to sabotage ourselves when we are ambivalent. The question then becomes what are you ambivalent about? Your husband? Your success? Your lack of assertiveness?
The things that led me to offer this perspective are that you are doing things to cause a rejection. You are silent rather than engaging, hold back sexually, and have not been assertive enough about your own needs in the relationship. Your resentment toward him sounds displaced. You may be angry with yourself for not being able to accept responsibility for your own well-being.
The couples counseling is good, but I think you will want to have some individual therapy to unravel what is underneath this. My concern is that the fantasies you have about your single life are just that. You may be sabotaging a good relationship that will be the cause of your lament in the future when other relationships fail to measure up.
Take what I am saying with a grain of salt and use it as a possibility to be ruled out. If you haven’t already you may also want to consider an evaluation for antidepressant medicine.
In any case learn everything you can about what brought these feelings on, how the relationship progressed to this point, and what your options are. My experience has been that couples should learn everything they can about what has happened. First it may be what helps them repair the relationship. Secondly, if they do split, it will be very helpful for both of them to navigate their next experience with intimacy.