A persistent rumour is that his ex-wife was also his unofficially official editor, which is why the comic started getting especially weird (arguably, down-turning) in about 2014 - although the breakup was said to be amicable, the stress of the breakup and the loss of her as a creative resource probably had something to do with it.

A similar rumour is that he doesn't rely on his current partner in a similar way, either because she isn't interested in unpaid work or because Jeph doesn't want to fall into the same old pattern.

I have no way to substantiate any of this, it may just be a coincidence of timing, but it implies that Jeph doesn't have an editor, certainly not one with expertise nor used full-time.