This isn't all on you to manage, John needs to be the one putting up boundaries with his friends. I mean, yes, Ella is trying to mean girl you out of the relationship, but why is he allowing her to treat you like that? She literally fed him from her hand but why did he just let her? He no longer has the excuse of not knowing what she's like because she did you both the favor of showing her true colors right in front of him! I'm sure he wants to give her the benefit of the doubt but if he loves you, then he needs to be on your side. He needs to make it clear that he won't tolerate Ella treating you with anything less than simple respect.