What Can I do ????????????

I m In Love With Him 1 year ago. now in between we are in love deeply love but today suddenly i see that one girl in he’s whatsapp profile  i dont know whos she, i ask to him whos she??. but he says i dont knw what u say i knw see that pic in my phone i don’t know any girl also say that he check friends phone  but that picture is see only in ur phone . i don’t believe in that . I love him very Much i cant live without him please help me what can i do in this situation …..            please help me otherwise i have only one choice die…..