“Past and Present” is episode eleven of season three of Stargate SG-1.
SG-1 arrives on a planet, Vyus, where the entire populace is suffering from amnesia and cannot remember what happened prior to an event a year or so ago, known as the Vorlix. The children and elders are also missing.
Before the Vorlix event, someone came through the gate called Linea – an extremely dangerous individual known as the Destroyer of Worlds who was first met in the episode “Prisoners”.
As it is SG-1’s fault that Linea escaped, they feel responsible for what happened to Vyus.
Daniel gets involved romantically with one of the people, even though he only truly lost his wife in the last episode, “Forever in a Day”. At least he acknowledges that, rather than it being completely ignored. Even considering that they had effectively been apart for some time (although unwillingly at that) prior to her death, that still seems like a quick rebound.