Tell me what Ido please help?

my ex dumped me after 7 yrs together I totally loved him,but he wanted space,was partying alot,wouldn't take my calls.and I suspect seeing other women.I loved him,cried all the time and it hurt..then I met a guy I Have now bee seeing 6 months,i really like him and he wats to marry me..now my ex is going crazi wanting me back,sending me money,saying he will kill himself if i don't go back..i still like him,and like my new guy..it is driving me crazi..what do i do??