Asitis is right, tell him it's a boundary and learn from it. Make the discussion happen when you are prepared for it rather than at some point in the future when you may not be and it gets out of control.
The other reason for sooner rather than later is it'll stop it eating away at you as it seems to be now.
- Nobody has ever learnt anything important from happiness and success; problems make us grow - Consult your plan, not your feelings - If you haven't set goals, how can you expect to achieve anything?
