Tory MP Andrew MacKay resigns as Cameron Aide over expenses
But at the same time his wife also claimed the full annual sum for mortgage interest on a constituency home - meaning they appeared to have two second homes but no main home, sources said.
Mr MacKay will now appear before the internal review panel being set up by Mr Cameron to review "excessive" claims.
There is no question of him having the whip removed.
Ms Kirkbride, who was previously a political corespondent for the Daily Telegraph which has sparked the latest furore over expenses by printing leaked details of claims, registers the London property as her main home and takes second home allowances for the Bromsgrove home they also share.
The resignation appears to suggest that the newspaper may be preparing to focus its next set of disclosures on the various pairs of married MPs in the Commons.
Previous controversies have surrounded claims by Tory couple Sir Nicholas and Ann Winterton, married cabinet ministers Ed Balls and Yvette Cooper, Labour backbenchers Alan and Ann Keen and Northern Ireland first minister Peter Robinson and his fellow DUP MP spouse Iris.
The Tory panel, which is awaiting the appointment of one further independent member before starting work, was set up by Mr Cameron earlier this week to examine "excessive" claims.
He has vowed to strip the party whip from any who reject its findings and refuse to make repayments.
