i felt like my life is ruined how can a person do like this ?

a person who loved me before 2 days and do such thing .

i was weeping alot i couldnt believe he can do like this .i said him i ll pay him everything just dont contact my family now .then he said was blackmailing me that he will tell my cousin who is very rich and likes me and financially help me when i ask him .he is very jealous of him and he said i will contact him on FB etc .

after every sometime he text my sister and i dont knw what he tells her .and my sis contact me ..