Not SURE IF IM IN Love Anymore

I dont know but i have recently falling back from the one i have been with for 4 years and im not to sure if im in love with him anymore . I have gotten distance from him and i cant get back close to him my heart wont let me . I dont tell him i love him anymore , he says it all the time and i never respond too him , it goes in one ear in out the other.He also is talking about marrying me MARCH 8th & i dont want to lead him on to thinking i want to marry him and having him thinking im in love with him . As time went on i have lost feelings from the arguements , lies , ect. What should i do i dont know what to do anymore ! Should i tell him or should i just wait to see if feelings come back .