Gen 1- Night Light and Twilight Velvet got married and had Shining Armor and Twilight Sparkle
Stellar Flare and Sunspot got married and had Sunset Shimmer and Sunburst. Sadly, Sunspot died from illness.
Firelight is a single father who raised Starlight Glimmer

Gen 2- Shining Armor married Flash Magnus a few years after his return. They had two kids: Golden Shield and Aurora.
Twilight Sparkle and Queen Luna married and had Noctyx. Twilight had an affair with Flash Sentry and had Delphinium Sentry.
Flash and Princess Sunset Shimmer married a few years later and had Autumn Skye.
Sunburst married Starlight and had two kids: Dusk Glory and Midnight Sun. They got divorced a little bit after Midnight Sun's birth.
Celestia and Chrysalis got married and had Princess Naiad.

Gen 3- Golden Shield and Aurora are cousins with Noctyx and Delphinium Sentry
Noctyx is cousins with Naiad.
Noctyx and Autumn Skye are half-siblings with Delphinium Sentry.
Golden Shield and Midnight Sun are cousins with Autumn Skye