I took out debtfor my ex. is he liable to pay

i was withmyex for seven years, house the works. he recently left me for sum teenager and left be totally gutted. when was together we both had sum debt but i had good cedit rating and he didnt. wejoinedour money together and i tookout a loan in my name to cover both our debt. we also spent moneyon my credit cards when we was together.at the momenthe is paying half of the repayments but im worried he will stopand leave me lumbered with all our debt becuz its all in my name is there any kind of legal contract that can b drawn up so he is liable to still pay half of the debt?