Where did the time go?

I'm wondering if I'm insane here. Yesterday I took my kids and we were gone for four hours. My adhd spouse is working on tiling a shower right now. He had two rows left (6 tiles) to finish the back wall. In those four hours me and my kids went to place a floral grave saddle at my dad's grave, went to two different craft stores, three home goods stores, got dinner at a drive-in (took a half hour to get our food) and went to a separate restaurant to pick up ice cream for dessert. When we got home, I expected to see my husband relaxing after finishing the back wall and maaaaybe even starting one of the side walls. Imagine my surprise when he was standing there just starting to put up the last two rows of the back wall. I said, "Oh... wow. (Truly stunned.) I thought you'd be done with that by now - it's been four hours." He immediately got defensive and snapped, "I thought you'd say that. I had to cut some tiles, take the trash out and go to the bathroom." So, I immediately started trying to piece together the time in my head to give him the benefit of the doubt - Maybe he cut up all the boxes for the recycling. That would take awhile. Maybe the bathroom visit was lengthy. Maybe he worked out a pattern and cut ALL the tiles for the side wall. I went for a walk to blow off steam, so I wouldn't be mean and said nothing when I came back. Today I went out and looked... All the boxes are still out there. None of them cut up. So trash would've taken 10-15 mins. There were maybe 2-3 tiles cut up, so that would've been maybe a half hour. Bathroom...? Half hour? So what was he doing for the other two hours and 45 mins? He didn't START the final two rows till we got home. So he wasn't tiling. All the advice for the non-adhd spouse is to not get mad or question them. He tried to cheat on me years ago and has lied to my face for years. So how am I not supposed to care that he can't account for nearly three hours while we were gone? Am I the only one dealing with this? It's absolutely crazy making.