I am not dismissing this possibility. However, as I said she turned cold immediately after the wedding. Perhaps even at the end of our honeymoon. Affair should have happened prior to wedding if it was the reason, but then it would be strange for her to go on and have a wedding.
Having been on these boards for many many years, I will say that it is almost always true that when a marriage breaks up this quickly, there was an AP in the works before the wedding. Why do they go through with the wedding anyway? It is such a big production, it is embarrassing to tell your family and fiance that you want to stop it, they think maybe they can let go of the AP.
Since you were together such a long time before marriage, it is probably not an issue with her discovering she's gay, or that the sex isn't good. And it doesn't sound like you suddenly turned into a different person once you married her. I'll assume you're not an alcoholic, abusive or a gambler.
The loss in her life could have triggered an affair at that time.
But my advice is this - if you don't have kids - let go of her. Because this kind of problem so early in the marriage is likely to reoccur. I speak from experience. My ex-husband of 24 years, slept with an old girlfriend the night before our wedding. I should have just divorced him when I found out. Instead, we "reconciled", went on to have three children, were married for 24 years. BUT - he had an affair when the kids were pre-teens/early teens which devastated them, we reconciled and then several years later he left anyway. Looking back, I think there were more episodes of cheating that I was not aware of at the time. And my adult children pay the price for my poor choice to keep this man in my life and make babies with him, as he is a disappointing father to them now.
Maybe she's not having an affair, maybe she was just so caught up in the fantasy wedding that she wasn't thinking about whether she really wanted to be married. But I'd be willing to bet she's got another guy, and those "impulsive" trips might have been to meet him somewhere.
Or maybe she just has serious mental health issues - if that's so - do you want to take that on for the rest of your life?
This crucible can be an excellent time to become a better version of yourself. Use that. Focus on your growth. Leave her be. This early in a marriage should be a time when you are full of love and affection for each other - the absence of that is a HUGE red flag, whatever the reason.
