I think Lewis is a bad sort - partly because of things that have been reported about him and partly because of a hunch (I realise that has no credibility).
Lewis and Lottie have been photographed having quite bad public arguments a few times. I doubt their relationship is rosy. It just isn’t as dramatic as his relationship with Caroline for whatever reason - maybe their dynamic is different and/or Lottie is more emotionally composed.
He was suspected of cheating on Caroline or at least being in contact with other women more than once.
Is it a coincidence that his past two relationships have been with wealthy, vulnerable women that have apparently financially supported him or does he target that type deliberately?
He was/is involved in some seemingly dodgy social media finance venture. He doesn’t seem to have a job otherwise.
After ringing the police (as he should have) he made vindictive comments to Caroline about how the phone call would affect her reputation. I think it was something like “you’re ducked now”. I think this indicates he was motivated not only by self-protection.
Despite publicly appearing to support her and not pressing charges, I think he was manipulative and enjoyed Caroline’s downfall in the end. After all, he sent an ex girlfriend a photo of Caroline’s blood all over the bed (why would you think to do that? Taking a pic as evidence is one thing but sending it to an ex partner is another) which he would have known could easily get into the hands of the media and inflame the situation.
He also quickly started a new relationship with someone who, if not friends with Caroline certainly seemed to be closely connected to her life. This relationship was said to have begun at a memorial for Caroline, which I think speaks volumes about how he really felt about Caroline.
Caroline abused him that night and he was a victim but, in my opinion, he is an immoral, manipulative, parasitic grease ball.