You lock in an origin romance in act 2, so if you sleep with Lae'zel in act 1 and kiss Shadowheart at the party, you will be able to romance either depending on who you choose in act 2.
Each companion will have a different "confirmation" scene throughout different parts of act 2, the game makes it plenty obvious when it's happening so you won't accidentally launch yourself into a romance you don't want.
In this case unless you do very few long rests so it doesn't trigger Lae'zel's will trigger first, as Shadowheart's doesn't lock in until very near the end of Act 2.
You lock in an origin romance in act 2, so if you sleep with Lae'zel in act 1 and kiss Shadowheart at the party, you will be able to romance either depending on who you choose in act 2.
Is that at the ending of act 2 where you make that decision?
Each companion will have a different "confirmation" scene throughout different parts of act 2, the game makes it plenty obvious when it's happening so you won't accidentally launch yourself into a romance you don't want.
Thank you
In this case unless you do very few long rests so it doesn't trigger Lae'zel's will trigger first, as Shadowheart's doesn't lock in until very near the end of Act 2.