I’m 24 in a relationship with a 51 year old man, h

I’m 24 in a relationship with a 51 year old man, he kept his age secret and I didnt know he was that old and the fact that he has a kid my age. He sponsored my school and responsibilities, now he wants to marry me. I dont know what to do, I’ve been spoilt and I worry if I’ll ever find a man to care for me the way he does. I’m of marriageable age and dont know where to start a relationship. I’ve got a sick dad that I care for through him, I dont have any source without him…… I’m stuck between to marry him and face the consequences of polygamy or not to marry him and start life all over…..