Verrouille
If you felt so bad when masturbating,your choice to wear a chastity belt,even if extreme,is understandable.
Have you sex with your girlfriend or is it platonic,true love but without any sex?
Anyway,take care to take the cage off sometimes,even when your girlfriend will get the key,to be able to be erect(even if not masturbating);it would avoid some damage to the penis.
Even if you don't feel well after masturbating,it is logical the urges increase a lot.