Foggy recolections.

I was just wondering how many this happens to or what to do about it.  Say your SO asks you something and you answer it how you remember, or how you think you remember it because this is what your mind is telling you what happened. I feel I do this a lot but it gets perceived as me lying about it and I dont know what to say or do so I just go along with it and say Im lying about whatever it is. Its hurting my marriage, not the only thing but still a big part of it. I dont want to say that thats how I remember it but then Ill just be making an excuse and not taking responsibility for whatever it is. Im just so lost on this and it drives me crazy because I have no idea what to do in these situations. Like today I woke up later, spent time with DW, making some changes so I wanted to lay in bed with her and it was nice. i Felt good after getting up. The kids were up at this point so she said one needed changing. I did that and got a pull up for the older boy. We went into the living room so they could watch tv and give mom some time to rest. I changed the older one there. She then asked me some time later when im at work that it wouldve been nice to tell her that I didnt change him. I said that I changed both of them. In fact I know that i did. I distinctly remember doing so. It hurts that she doesnt believe me but I understand why.