I thought I knew my wife after 20 years, but she surprised me. Apparently, being direct with me was terrible for her, just the most emotionally draining experience imaginable for her, and she got tired of it- but rather than tell me that, she just stopped being direct and expected me to pick up on it, and when I inevitably didn't, she decided the relationship was over- but again, she didn't tell me that, just started boinking our son's best friend's dad, then when I started to figure it out, told me I was crazy for thinking it, that he was just a friend... When she finally did tell me she wanted to divorce (one year ago today, matter of fact), she didn't want either of us to move out, she expected me to be ok with continuing to live together sharing a house (and bed!) while she screwed her side piece... I moved out so quickly I didn't even have furniture, just slept on an air mattress on the floor for the first couple weeks... Then after I had signed a year lease, I found out the other guy lived right around the corner from my apartment... Rather than randomly bump into each other at the grocery store, I decided to call him (son's best friend's dad, remember?) Turns out, she had been lying to him too, told him we had been separated "for some time", just living together for the sake of the kids... He seemed genuinely horrified to hear that wasn't true, apologized for his part, and said he was going to break it off with her. I didn't really believe him at the time, but as things have played out since, while she was trying to make me think they were still seeing each other, I could tell they weren't - my son lamenting not seeing his friend much anymore for one. Some months later after I had dropped off the kids with her, she let it slip that "he's always busy now". Gee, I wonder why...

Anywho, you think you know someone...

People change and feelings change in 25 years, and with children in the house we're more like coworkers than a couple now. There's plenty of opportunities for conflict and so little time for each other. So yes, it's natural to doubt in such circumstances.