I think Chad never loved Sage, its not like you love everybody you get relationships with. However, I dont think that he wants to hurt Sage
If Melanie is indeed Chads girlfriend (like DPC is trying REALLY REALLY hard to sell), that means that she is a slut because of what she does since ep4 with the MC.
What I think might be happening is that Melanie and Sarah (being ultra gossips) know who Chad is "dating" and are helping him get out of the relationship with Sage in what they feel is the best moment to do so. And what could be a better moment than when Sage is starting to develop feelings for the MC and/or is a moment when Sage has the MC to "put her pieces back together"?
If Mel and Sarah wanted to break them up... They are already broken up since ep3, what was missing was confirmation.
However, this isnt what is happening because there isnt enough drama for Being a Dik, so our theorys must be true; Chad is gay and indeed with Troy, Melanie and Sarah know it because they are ultra gossips and they pressured Chad into doing this because they want Quinn in power of the HOTS and the MC wont care because he is having sex every single one of the HOTs and that wont change if the president changes.
And with Quinn as president, everybody will become a gloryhole drug selling exotic food named dishes on a restaurant menu