Is your party permanent or can you change members out throughout the adventure? Recruited companions will be at camp when not in the adventuring party, and can be swapped in and out at camp. After the first act however you are going to have to commit, also just like in real life.
I read the post by Larian differently than the interpretation I see in this and another, similar thread: 'During act 1 you can switch companions out without consequences. After act 1 you will have to commit to the character(s) you want to romance, just like in real life.
That is however not what was asked, and not what was answered. There was no mention of romance or relationship - just if we can freely switch our party composition, and according to the dev just like in D:OS2 it will be possible only in act1, and after that we will have to choose a permanent party. And considering that everything that we have seen about BG3 is D:OS2 v2.0 that wouldn't be unlikely.