Trust, respect and communication are the three pillars of any valued D/s relationship, plus of course the sub must be able to fully submit themselves to the dominant - no in between state of sometimes being submissive when it suits and definitely no 'topping from the bottom'. Clear boundaries are Read more… essential for the dynamic to work.

Sit him down and get him to talk to you about it. Perhaps he's just gone off you - in which case talking about how to spice things up will help (e.g., using blindfolds and toys more, arranging 'anonymous' hotel meets, role play or perhaps more kinky play). Communication is key.