"Sent him information" means in written form ......
Call his bluff and say, as a poster has suggested above, that you need to know immediately who sent the information - because this is the second time they have done this (or is he claiming it's a different person from the last time?) and you have reached breaking point and will be suing them for libel and harassment.
Tell him that, as you'd partner, his place is to support you in this and there are absolutely no ifs, buts or maybes about that.
Tell him you have booked a solicitor appointment with one you found via the Law Society website who specialises in libel and you need their details urgently before that appointment.
That if he doesn't give you the email address or any details at all he knows, you'll consider that he's not on your side or the side of your relationship. That there is no reason whatsoever he shouldn't support you, and you will be forced to reconsider your relationship if he doesn't. You want a loyal.partner in your corner, as anyone would.
This fucker needs some of this shit back.
He'll tell you nothing, of course
Because he's making this up, just like he was the last time