The bad news: due to the insane nature of yesterday (long story--it involved an intense amount of work to be done by me and the added fun of putting together a pretty extensive last-minute work project for him, which was finished and uploaded to a 24 hour copy shop at around 1:00 this morning) I didn't really get a chance to bring up the idea that we should set boundaries around how to avoid a situation like this in the future, and to establish/make clear my own boundaries around his drinking and other behavior. Now resolved to do that tonight and to insist that it gets done.
The good news: The friends that D went out with on Monday night confirmed that everything had been very fine and normal, that he didn't seem intoxicated at all, and that there were no issues with women. So it seems that he was telling the truth after all.
The bad news (or, considering my own recovery, perhaps good news): That still doesn't change the fact that I feel like I trusted him to know his limits and he violated that trust. It may have all been just a mistake, like he said, but it doesn't change how I felt about the situation.
The good news: Assuming there really have been no phone issues, today marks one year sobriety for D. And while we (quite obviously) still have a lot of issues to continue working through, that fact is still pretty darn cool when I consider how differently we both probably would have handled this situation a year ago.