That will depend on things like where you are from, where in the world you are going to meet your Irish boyfriend and how long you plan to be with him.
Yes
yep
Slovakia is in EU and therefore you don't need tourist visa if you are Irish cityzen.
Yes sure
Yup
Yes, you may need a visa to travel to Ireland depending on your nationality. It is recommended to check with the Irish embassy or consulate in your country to determine if you need a visa for your trip.
Yes you do, even for tourism visits. There is a Thai Consul in Malta at Bisazza Street, Sliema.
yes
If your boyfriend comes back with a Visa, you are able to marry him in the United States. You will need to get an immigration Visa rather than a tourist Visa.
Yes
No. Bulgaria and Ireland are both part of EU.
No. Both Ireland and Cyprus are members of the European Union and there are no visa requirements for EU nationals.