Sylvia Crozier was Wendy Crozier's stepmother. Sylvia married Wendy's widower father and was sufficiently close to her stepdaughter that Wendy sometimes referred to her as her mother.
In April 1990, Wendy had Sylvia over for lunch so that Sylvia could meet her partner Ken Barlow. At that point, Ken had recently lost his job at the Gazette, adding to his woes following his separation from Deirdre. Having been forced to cancel a weekend at Alton Towers with Tracy to meet Sylvia, Ken didn't want to be there and, while Wendy was out collecting Sylvia from the train station, he went out for a walk to get space. While they waited on him, Sylvia - unaware that Ken and Wendy had got together while Ken was still with his wife - got the full story out of Wendy, cutting through her attempts to justify herself by claiming that that Ken's marriage had been on the rocks.
The day got worse from there as Ken arrived back at the house and, after a brief introduction, stayed quiet through lunch. Wendy chided Ken for not making an effort when she got a moment alone with him in the kitchen, but a perceptive Sylvia had worked out what was going on and told them she preferred that they didn't put on an act for her sake. Sympathetic, Sylvia offered to listen to their problems, suggesting that it may help to talk it through with a third party. Taking her up on her offer, Wendy launched into an attack on Ken's character, accusing him of creating his own pressures.
Although Ken ended up impressed with Sylvia, Wendy felt he'd let her down and, after Sylvia left, accused him of trying to destroy their relationship.