Stress. Stress makes a person do crazy things.
Sandy had been back at work full time in a stressful job for two years at that point. Along with looking after kids, doing homework, and all that jazz it doesn't leave much time for us to relax.
Sandy needs a lot of time to herself to centre herself. It's always been the way she is. The lack had built up and she knew it. She was almost cracking up even before the boyfriend came on the scene. We both knew it and we're trying to deal with it but what time we could make simply wasn't enough.
She suffers from sad (winter blues). It was mid winter, and we haven't had a good summer in the uk for years.
She's bored. Midlife crisis bored. We are looking to move job and move country just for an adventure. She was feeling hemmed in badly.
All this leads to a woman who was on the edge of breaking down. Not an end of the world mental breakdown but bad enough. You know when you feel boxed in on all sides and can't see any way out. When you aren't thinking straight and your emotions are all over the place.
Into all this came the boyfriend. I won't say much about him but in the end he turned out to be a poisonous character. Consciously or not he tried to come between us. Pressured sandy into seeing him too often, into letting her feelings go when she was trying to be more careful with them. Even threatening suicide when we were trying to back away from him. Since she did care about him then she kept being drawn back in by it.
In the end she cracked. I wish I could say I acted perfectly but I was too angry to be calm. I was forgiving but angry, stressed, and harsh at times. Felt very unsure of us for a while wondering why she would apparently value him highly enough to put our marriage second. Not realising quite how much the stress had affected her judgement. And only finding out as we talked more how much he had been lacing us with his lies.
Rebuilding trust is hard and takes time. I still occasionally wonder if she is cheating. I know she isn't, but I also know something I didn't know before. She is able to lie and be believable. So trust has to be on faith now, based on love alone. That's harder now than it used to be. It helps knowing that it wasn't done with malice but out of stress and a desperate need to avoid conflict.