Im disabled so i cant get married

I have severe mental health issues stemming from recurrent trauma. I am registered disabled and deemed unfit to work as it greatly effects my everyday life. I have been engaged for 14 months to the most amazing partner i could ever ask for, and were desperate to marry one another but if we do, i lose everything, i lose all benefit/entitlements and his small wage cannot cover the two of us, rent, bills, living expenses or a family. So were stuck. He suffers low self esteem and ptsd after being held at knifepoint and almost raped at age 9, and did not do well at school afterwards so he's feeling stuck too. We both feel stuck and its all we want😭💔