Everyone is talking about case size vs. wrist circumference but that is the wrong comparison. You should be comparing wrist width vs. face size. Circumference only matters when fitting the band. Both of my wrists have the same width but one has an extra centimeter in total circumference.
The face vs. the wrist width is what will be noticed the most.
In my case, I have 167mm circumference on the arm I"ll wear the watch. Seems like 42 is a lock, right? Wrong. I have very "round" wrists. Only 50-55mm width. Given the OP's width of 65mm and that the 42mm looks to be only just barely not oversized, it is clear (also based on other factors such as my own tastes) that 38mm is the only choice for me.
But if my wrists were flatter, and thus wider, I might be going for the 42. It's width that matters, not circumference.