Discussion problem

me and my girlfriend had been living together for almost one year now but the only problem i have with her is that she like discussing every problem both little and big ones,the problem is that i don't know how to discuss mush especially when it comes to the relationship problems i do give her answers to her questions but she never agreed on it she always want me to discuss it with her this Brings big Problem especially when kept silence and reason for my silence is that really i don't know what to say to continue the discussion,this problem almost end our relationship i really love her and i cannot afford to lose her please can anyone help me out?