"[They should be] chaste, neither [of] those who commit unlawful intercourse randomly nor those who take [secret] lovers !!"
Quran 4:25

How exclusively Allah mentions the fact about people keeping "secret lovers" !!!

So here my people the Bf-Gf or any kinda relationship between a boy n a gal is condemned by Allah..

Islam rather encourages "halal" steps i.e. early marriage.

May Allah save us all from this fitnah of Shaytan and help our brothers and sisters already in this trap.
Ameen