Question, is the only gay scene in the game the first one???
The character Nick, introduced in the bonus scene, if you played it, will be one of two romantic rivals. Both Alexander and Alexis will have the choice of interacting with one of these rivals, the other being a girl. The ways you interact with them will actually be the brunt of the variation to this story. Alex can be bisexual, choose only to interact with Nick, foregoing Alexis, or can be played as choosing all the straight options.
That said, I very clearly code Alex as being somewhere in the middle of the spectrum on sexuality. There are times, like in the first release where they talk about a D&D campaign where he seduces a male character, where this queer-coding will be more explicit, and other times, like when I have the twins singing lyrics from Moulin Rouge at one another, that might fly under the radar.
Just as there's no forcing anyone to experience NTR in this game, there's no forcing anyone to go along with the incest, the straight, or the gay content. This game truly is more about making choices with these characters and seeing how they affect the relationship that I set up in the first place.