Sorry you need to be here. The shock of the discovery (or the disclosure), as well as the relief that comes after having "the conversation" is well known to us, even part of the process. Part of the process is often also the feeling that now that you know and your spouse has shared the truth, you are well positioned to move forward with the marriage. Unfortunately, that feeling often doesn't--can't--last, because we haven't yet incorporated the fact that our spouse does not see things the way we do. Sometimes for our spouses the secret coming out makes them want to act on their sexual orientation, and they believe that because we now know the truth, we should support that.
I'm sure you'll get a range of responses, both here and in the MOM section. I will tell you straight up that my immediate reaction to your question, "How do I master my own feelings and emotions, regain that strength and confidence I once had, and move forward?: was "Leave."