Why couldn’t he get hard?

So there’s this guy I’ve been down for for a while, but since he was in a relationship I never tried anything even though he would flirt with me regularly. So he recently broke up with his gf and basically implied to me that he’s very down to hu. So I went over to his house one night and we were hooking up and going to fuck but he just couldn’t get hard. He was hard at first but then just went completely soft. He then told me that he drank earlier (alcohol) and that’s why he couldn’t get it up. This made zero sense to me because he didn’t seem drunk at all, didn’t smell/taste like alcohol, and why would he drink on a Monday night if he knew I was coming over? So I’m wondering, do you guys think he was lying? I feel like maybe he’s just not over his ex, or nervous because I’m his first since his ex or something like that. But then again, he was also supposed to drive me home but in the end he couldn’t due to being intoxicated so that was the one thing that made him drinking seem true. But other than that, him saying he was “drunk” just made no sense, so I’m wondering if the reason could be more psychological. What are your thoughts?