The player is able to control which potential partners Alexia sleeps with. It used to be that every single literal incident of NTR was totally avoidable, but in a few cases when a player has already chosen to go down the Andras OR Jezera route (via the mid-corruption events) it will continue to show some of those scenes.
What this means in practice is that if you wish for Alexia to ONLY sleep with Jezera and other women, it will be possible to have that be the only NTR that takes place. There are some hetero scenes planned for that route (one of which already exists), but the current planning is to make those scenes continue to be optional well after the Jezera route lock.
So in short. Yes, it's possible to just have her sleep with women.