He is 10months old, house trained with very rare accidents but every time he is left with my boyfriend he just pees everywhere... they are not like little excitement pees but proper big ones as well. Other thing is when he takes him for a walk and off the lead he never wants to come back to him but he never does it to me... he just seems to be so much naughtier with my boyfriend than with me... but we got him together and both looking after him equally so I don't understand why??

He doesn't care for your b/f; showing you the only way he knows how. Something the three of you are going to have to work out.