A couple of theories of what happened to Shaw - Spoilers

i think David realized Shaw was the only human to experiment on. what isn't clear i think is when he came to this conclusion. He loved Shaw, as much as he could and he felt bad for having to do what he did, but it was necessary to complete his work.

Yeah I think the real qeuestion is just how long he waited. Like I said, it just makes her death cheaper if he immediately ripped her apart. Well I think it does

Perhaps, he gave Shaw children, a legacy. Since she could not bear any children. David gave her what she could not have.