Northern Ireland has a lot of things going for it and is much cheaper than the Republic of Ireland too.
Game of Thrones Studio Tour at Linen Mill Studios in Banbridge.
GoT Willow Throne at Belfast International Airport.
Dark Hedges location from GoT - don't drive cars up as vehicles are damaging the tree roots!
Giants Causeway and Visitor Centre. Mind you, it's free to go onto the Causeway but is a trek. Pay and its a short walk.
Belfast - Titanic Quarter and all things relating to Titanic heritage. Former H&W drawing offices is now a heritage hotel which you can visit. Lunch at Titanic Hotel Bar is recommended for first class food! Shopping.
Ring of Stones just outside Lisburn. Standing stones from the Neolithic, I think.
Ulster Folk & Transport Museum in Cultra - DeLorean car is there.
Ulster Folk & American Folk Park - history and how people lived.
Causeway Coast is a popular driving route - Dunluce Castle part of it.
Rathlin Sound cruise.
Lough Neagh.
Fermanagh Caves! Beautiful.
Most of the above is in Antrim and Down, so easy driving distance!
There's a lot to see and do in Northern Ireland! Your money will go further and it still fits in with your Emerald anniversary.