When a couple each have a DSP claim, if one person is on a benefit (PRSI-based) scheme and the other is on a means-tested scheme, the maximum amount that can be paid is the same as if one person was claiming for both partners. As you are currently on Illness Benefit, your partner's Jobseeker's Allowance (which is means-tested) is the one that's reduced.
When you return to work, your partner should notify his local office, at which time his entitlement will be means-tested based on your wages. As it appears you have supplied salary details, the means test has probably already been carried out.