Friends what do u think i should do? should stay or should i go.

have been dating this gal for the past 4yrs my parents love her to bits, but something happend some weeks ago, i went to her house and her mum was so cold to me. i did not say anything not until last week her mum called me and told me to come to the house that she want to talk to the two of us.
my friend in front of me and i quot ( my son you know i like you, but you can not marry her over her dead body). my friend what should we do