Labor Party chairman Amir Peretz may have been hoping for a honeymoon, but his marriage to the 17th Knesset got off to a rocky start with Wednesday's budget vote. Despite stipulations in the coalition agreement that Labor MKs would support the budget, three "rebels" - Shelly Yacimovich, Shalom Simhon and Yoram Marciano - embarrassed the chairman by intentionally absenting themselves from the vote. Nadia Hilou was expected to as well, but was persuaded at the last moment to vote in favor of the budget. Hours before the vote, Prime Minister Ehud Olmert urged Peretz and Gil Pensioners Party chairman Rafi Eitan to enforce discipline in their parties. Sources close to Peretz said that he was doubly ashamed that one of the rebels was Yacimovich, his long-time ally. "Peretz has leaned on her a lot and considers her a close ally in the party," said a Labor official close to him. "It was very hard for him to watch her disobey." Peretz reportedly tried everything to sway Yacimovich, including calling an emergency faction meeting and sending Tourism Minister Isaac Herzog and Minister-without-Portfolio Ophir Paz-Pines to talk with the rebel MKs. Yacimovich and Peretz reportedly got into a heated fight after the faction meeting, prompting many to joke that the two had had a "lover's quarrel." Even as she maintained her position, Yacimovich insisted on defending Peretz's support of the budget. During the election campaign, Labor officials said that Yacimovich earned a reputation for being the ultimate Peretz-defender, and he sent her to shield him from the press. Although the three MKs will be punished by being banned from giving speeches or filing motions in the Knesset, a standard practice, sources close to Peretz said he was concerned the rebellion did not bode well for his future leadership. "Peretz's strong position in the coalition depends on his ability to hold the party together," said a senior Labor strategist. "The party falls apart and he loses his power." Peretz has already faced several rebellions to his leadership from veteran party MKs. During the vote, Peretz was all smiles as Likud MKs taunted him for voting for the same budget he slammed in a Knesset speech less than a year ago. Peretz could not keep smiling, however, when the names of the three Labor MKs were called out during the vote. In the silence following Yacimovich's name, Moshe Gafni (United Torah Judaism) called out to the vote-counter, "Hold on, maybe she'll show up yet." MKs sitting close to Peretz said he looked pained by Yacimovich's absence, and his serious demeanor only grew as Marciano's name was called and Gafni taunted further, "Don't worry, he's just out looking for Shelly." "The real reason this hurts Peretz so much is that if he were not the party chairman, it would be him leading the rebel MKs," said one Labor MK. Peretz's moment in the spotlight as the outspoken socialist MK had ended, said sources close to him, who added he was feeling the responsibility more than even he had expected.