My number is not unlisted - this is deliberate on my part. I have no wish to 'hide' any more. But equally it would require an effort to establish where I lived and my number.
My kindest interpretation is that he was hoping I would answer, and we could talk, without him actually calling me, if that makes sense. But even so, it is devious. My son is grown and does not live with me. He is visiting over the summer as he is a grad student. We get on well and he regards it as 'home'. I think that upsets my xh, as my son does not want to spend time with him.