is lesbian stuff avoidable
You can choose if the girls do things with each other at all.
You can also choose if they do things with or without your permission.
There is also a setting where, it seems like someone is going to hit on one of the girls at one point but you stop it - the setting seems to just take that out of the game (haven't seen it pop up yet, though).
And the last setting is the girls showing interest in anyone besides you.
So, basically, turn all of them off and you are all of the girls' whole world (although the backstory/set up with Ava probably still happens). Honestly, although I'm keeping them all on, I applaud the dev. We often see triggers for NTR/Sharing, but not usually for jealousy-based scenes. I think I've seen it once or twice before (The Seven Realms also does a great job at these options).
Now that I look at these, I had the 2nd option off... I didn't see the Ava/Alex kiss scene, just them talk about it. Guess I'll have to backtrack... was kinda disappointed when they only talked about it but didn't do it.