I split with my ex in November last year after 15 years together, engaged for 8, he's now demanding the engagement ring back after initially telling me to sell it. I told him despite what he paid, £3k, it won't be worth anywhere near that, in fact the highest valuation I've had was £500 which I told him. He thinks I'm lying and has asked for the ring or £3k and will not let up. I don't think I should have to return the ring or pay him any money but AIBU?