Female led relationships discussion

Bad news.. Me and P decided that L should stay in the chastity device for 4 months without cum. after only five days and half of chastity cage with a lot of teasng and denial he failed. Last time we have had sex he lasts a few strokes only so we decided that it’s over and for a month he wouldn’t be allowed to have sex at all. But 30 minutes ago P was teasing him while caged.. and after some “tongue games” at his little friend, we saw a big, single flow of cum going out from his cage.. not the usual “explosion” that i’m used to see when he cum but he released quite a decent load without a complete erection (as i told you, he was caged). So i didn’t want that and neither P does.. but i don’t know what to do.. P it’s not angry, to be honest.. she says that L was completely full and it was very difficoult for him to hold it even if, when he was almost having the orgasm, we both exhorted him to hold it back.. so she says that a punishment it’s not mandatory.. but she’s going too softly with him.. if i don’t punish him now he will think that it’s a joke and in those 4 months he can cum, when he wants it very hard, because we will “understand” his situation.. but i also don’t want to be always the bad one.. What should i do?..