There are no Constitutional restrictions against homosexual acts, but they are not protected as a right like Prayer is. Prayer is part of Religious Worship, and Freedom to worship under a Religious belief is protected under the Constitution.
A Man who chooses not to engage in homosexual acts already has Constitutional protections as a human. However, if he then chooses to engage in homosexual activity, while being free to do so, that activity does not then elevate him into the same protected class as being Human or a Man.
He can certainly perform homosexual acts, but they are not protected as a right. Only his right to choose them, not being a homosexual as a result of doing them. He's not a homosexual until or unless he performs the act...but he's always a Man so he never loses his Constitutional protections as a Man. However he has no protected "right" to be considered a homosexual because he can't be one until or unless he does what makes him homosexual and that activity is not a guaranteed right, only a preferred choice.