Get a life of your own so you aren't so attached to hers.
Getting married does NOT mean you two are connected at the hip. In fact, that path is one of the surest to divorce. Marriage means you two expand each others experiences, not become an island of 'you & her'. If you aren't as sociable as she is, you need to deal with that. Its not her problem, its yours.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh