boyfriend feels IUD during sex

So I've had the Mirena for almost 2 years. Last year he told me he could feel the IUD during sex and that it's not hurting him during sex but he can really feel it. and honestly if he goes too hard, then I'm kinda sore after. I thought maybe it was getting dislodged so I've been to the obgyn twice and gotten imaging done and they say it's sitting Abby low but not dislodged. Should I be worried ?