Hey. First of all l wondering where you gonna buy? Secondly lf you have any option to marriage. The best option is buying it after marriage.

ln other case, you could buy the house with him just like partner. Or he could buy and could give you some rights. For example you could stand in the building till your death etc. At all, there is a lot of option to make legally. But l really no idea how to your boyfriend wanna do it. l guess you dont wanna be object of any kind of trick, l think so you must gurantee yourself and your rights.

For an answer to your second question which is about marriage, lt does not matter, everything is common after marriage. The name or other stuff does not important after marriage cause when you get married then you take %50 of all things what you bought together with him after marriage.

greets.