FWB generally means a purely sexual relationship, but, in practice, it is difficult to have anything longer lasting than a one-time fling without having other aspects of a relationship based on physical intimacy, or sex. The extent to which there are aspects beyond sex range from enjoying each other's company or companionship, to liking or being friends in a platonic sense, to affection, to love, and more, or any of those choices. The answer to your question is there is no normal. To the extent it appears normal is a function of the choices those in FWB relationships make about how it will be carried out and what it involves. The possibilities (like shapes and forms) are as different as the people involved in them are different). Each couple defines its own normal either as a conscious choice or by how they behave (interact) with each other.