If you look at what's in the bill introduced by the government, in proposed paragraph 150.1(2.2)(b) you have the exception that the accused is the common-law partner and is not in a position of trust. That is the formulation that would better reflect the concern that I think Monsieur Petit was mentioning.
If the subamendment were to be worded in a similar way, it would read that the accused
(i) is less than five years older than a complainant; and (ii) is not in a position of trust; or (b) the accused is married to...
That is as you had proposed. The concern is that when you list them as (a), (b), and (c), from a drafting perspective that is not the correct approach.