I have not seen any reports of EW's relationship status. Only that he liked to stay in. Only going out if he had to.
In criminology and pscychology, there are instances where one person has a one-sided infatuation with the other. Certainly, if the focus person rejects them, they can 'lose it', even become unexpectantly violent.
That someone he knew visited or lured him outside is a strong theory IMO. All you've said here makes sense IMO, but we have no foundational proof about it since we aren't law enforcement. What bothers me is this person may be someone he met 'analogue' is what they call it. That means there may not have been a digital relationship! There may be no text or email. Like if it was a barber, coffee shop worker, gardener, repair person, neighbour, school or work peer, faith community, casual repeated encounter like seeing same person on a bus, etc. Those are 'analogue' relationships. And may be difficult to trace.
However, without case-specific evidence, your theory remains one of many theoretical possibilities so we are SPECULATING (I always point that out to not target anyone accidentally).