He could apply for a fiance visa to come to UK and you get married within six months. Then he applies after marriage for FLR(M) which allows two years settlement, if the marriage continues he can then apply for ILR.

Or you could get married outside the UK and he can apply for a spouse visa to join you here, which is also for two years and then he can apply for ILR

See here for information and requirements

http://www.ind.homeoffice.gov.uk/applying/generalcaseworking/spousescivilpartnersfiancees

and here also  http://www.ukvisas.gov.uk/servlet/Front?pagename=OpenMarket/Xcelerate/ShowPage&c=Page&cid=1014919208354

and here for more guidance

http://www.ukvisas.gov.uk/servlet/Front?pagename=OpenMarket/Xcelerate/ShowPage&c=Page&cid=1018721067257

Hi I am resident in uk ,and got Indefenite to remain so I would    like to know to require    for a mariage for a citizen United stated America .I want for my future husband to live in uk with me . Thanks