Is my 4-year relationship built on a lie, and should I walk away now?

Hi me and my girlfriend are dating since 4 years I don't have any past relationship but as of her, her boyfriend died during covid. when I met her she was a yes person even when not comfortable which I realised after a year.. so right now my situation is whatever relation we build was a lie or don't want to get into and now we literally talk less and all conversation just ends up in a misunderstanding, when I met her I felt she just lost the guy but it never feels she'll be getting over it. Also I don't know why she stays with his parents all this time I got to know recently. What would be your advice because I have tried to have peaceful conversations and many times even taken the blame but I don't know how to come out of this I do love the person a lot but absolutely have no clue that she even want to be with me because whenever I ask such questions there is no such direct answer but have a sweet compelling reply.
Is my 4-year relationship built on a lie, and should I walk away now?
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