Another DUP councillor has left the party in protest at its plans to share power with Sinn Fein.
Roy Gillespie said the DUP's decision left him devastated
Ballymoney councillor Audrey Patterson said she was saddened at the decision of the party to go into an executive with the republican party.
Earlier, Roy Gillespie, a member for more than 40 years, also said he was leaving for the same reason.
He was the third Ballymena DUP councillor to resign in recent weeks after Davy Tweed and Sam Gaston.
Mr Gillespie, a founding member of the party, said of Monday's meeting between Ian Paisley and Gerry Adams: "I'm still in a state of shock and mourning - I am devastated."
He said he had quit with a "heavy heart", but "the DUP have joined hands with an unrepentant terrorist party".
"My conscience and principles will not allow me to stay in a party which, I believe, has stepped away from all the principles it once held," he said.
Mr Gillespie said he would remain as a Protestant Unionist councillor.
Ian Paisley and Gerry Adams sat side-by-side for the first time
DUP Ballymena councillor Maurice Mills said people had to move in the direction decided by the electorate.
He expressed regret at Mr Gillespie's departure and said he had served the party well.
On Tuesday, MEP Jim Allister resigned from the DUP a day after Mr Paisley's meeting with the Sinn Fein president.
A number of DUP assembly members have spoken of their concerns about power-sharing with Sinn Fein on 8 May, but none has resigned.