fiancé issues

I know this may sound so stupid to some of you but my fiancé is 17 and his mum keeps taking his phone away and it makes me really annoyed sometimes I don't speak to him for up to 2 weeks and don't see him for 2 weeks it's really hard please don't judge him or his mum or me for writing this post but I need advise on how to get through it I've been with him since I was 12 Iam now 16 he's 17