DATING A BOY WITH STRICT PARENTS

Hi Everyone 
I'm 18 and I've been with my 20 year old boyfriend for about a year now 💕
His dad is super strict and won't let him out of the house, we only go on dates and have outings when he's at uni ( cause then his dad can't stop him)
Anyways summer is coming up and I really don't want to be indoors with him all day this summer and we can't go out cause of his dad 🙄
I'm so frustrated, what can I do ?