If this were a therapy session, I would recommend we spend some time discovering what it is exactly you are experiencing when it comes to this man leaving. I know his leaving you is tragic, but what are you noticing about the situation that got your attention when he left? Do you feel inadequate, abandoned, and stupid for being played and committed? Do you have anything significant from childhood that is being triggered here? Let's take some time to get you to know you better because you are going to be your best advocate in all this.
The reason therapy is a thing is because we think we know ourselves pretty well. In reality, we all have blind spots where many of our problems lie, that something like you are experiencing is triggered when it occurs. Your husband did not just leave, you wrote he left you for another woman. You say, "help." Going off of the reminder that you could have written a thousand different things about this situation, you wrote those things. Do you realize what this reveals about you, about how you view this situation and how you have a belief that there is some other way to do this or view this situation providing relief, hence the "help?" I know this seems like it's not what you came here for, but how you are viewing this situation and what is being triggered inside of you is really what we are dealing with, not just the husband leaving, but what it says about us, before, and now.
The "before" part is the part of us that is being triggered; that is the "blind" spot I refer to. You have beliefs and experiences that are in your brain that lies dormant, or at least we think they are dormant, until something significant happens, and then you notice something else about yourself. This is why reflective questions get you to know yourself better. Though I, as the therapist, may see things about you, or view your situation a certain way, none of that matters until you see it, and makes space for that in your life. As I asked before, are there any significant issues in childhood, inadequacies, or beliefs about yourself that are present here today in your husband leaving you....for another woman?
The brain works based on experience. Often the experiences we have are what tell us the world is a certain way, and we are a certain way, and experiences act as a frame of reference for future occurrences. For example, if in childhood I wasn't paid attention to, or my parents didn't allow me to fail because of their own anxieties, my brain makes sense of the world (harsh) and my ability to be in it (cannot be in it as I am). However, new beliefs can override the old ones if they are consistent enough. You can start to believe inadequacies about yourself from this recent marriage if you aren't aware they exist.
Your husband and you's relationship, what did you think about it? What did you notice going through the marriage about him or about yourself? Was this a surprise, or was there a part of you that knew parts of him that could not admit that this behavior fits? If you did not see anything about him, or your relationship, what did you miss, and what were you doing to miss it? These would be good questions to help identify where your head was in the moment, and where it is now, and identify thoughts you may not have said aloud before (hence, getting to know yourself, the blind spots).
So, we've identified beliefs about ourselves from childhood, or most recently, about the marriage and us in that marriage. We have talked about some reflective questions to focus on to help better understand us in that situation. Now, it is time for us to sit with all of this and accept the fact that it sucks and is painful.
Here's the deal with life, it's painful. The type of pain we will experience and why it gets our attention, not another kind of pain, is up to the formed beliefs and the subconscious way we hold it. You are in a state of pain, and that is OK, make space for this pain. One of the worst things people do to themselves is trying to fix or remedy everything they deem uncomfortable. It is not the pain that causes problems, but our belief that we should not feel this pain and that we need to fix it. You don't need to fix it, and you can (despite what your mind tells you) sit with this pain.
Your mind will tell you many things about what to do in the next couple of weeks or months. Your mind will judge you, make up stories, and flood you with inadequacies (possibly), your job is to notice them, make space for them, and remember that your mind does not control you, but it does exist. Your thoughts are not you, but they are there. You, a deeper you than the thoughts, get to choose what you do when the thoughts and pain come up. If you find value in learning and experience and know that someday this all has a purpose, then endure. Do not remedy your pain or try to avoid it; learn what it is like to sit in it. This will equate to a strength unlike you've had before.
You notice thoughts, distance yourself from them, experience the pain, and learn to sit with it, and you will become bulletproof in life. You will learn to experience life, while not letting it take away your experience. You will learn to go into situations your mind says you can't do or that you are scared of. You can imagine yourself standing firm while all the words, firey pain, and then remedy thoughts tell you, "you can't handle this." You won't have to respond to those thoughts; you notice them and continue to do what it is you care most about in this world.
Find that "why," and you can endure any 'how." What do you care most about? What is something you value in life? Go for it, live for that thing, and there you will find that experience, pain, or pleasure, will be your best teacher, and you can even find gratitude for it.