Can you add line breaks to the :after pseudo element?

You won’t be able to render HTML tags but you can set style like this:

.needs-space:after {
    content: " ";
    display: block;
    clear: both; /* if you need to break floating elements */
}

The main setting here is display: block; This will render :after content inside a DIV. And this pseudo element is supported by all latest browsers. Including IE. Saying this you should be aware of your users and their browsers.