Bloody hell. I wasnt expecting that.. im gutted for you, but i bet he feels worse.
Id just tell him, its just a lapse and not a relapse. Its only a relapse when hes back on it again as usual from what ive learned. A lapse is just once. So tell him just get back on track and its just a little blip. If he can get to the rest of the year, its just once in a year hes had it. Which is great. Id just keep reassuring him. So he doesnt have it again any time soon.
Was he on his own when he went getting it? Did he tell you when he was coming down off it?
Me personally i would want my gf say its.. ok dont worry, just get back to what you was doing and get back on track, but she dont, she shouts and shouts lol tells me go shopping, constantly saying we need this..go shop. I