The actress predicts that the pair, who have had an on-and-off relationship since falling for each other in late 2010, will have a long future together as a couple.
"I think it will bring them closer together," she told Soaplife. "I think they're really connecting at the moment now.
"They're really looking out for each other and the pregnancy will bring them together as a family."
Before she informs Gary (Mikey North), she is struck a blow when he reveals he feels more comfortable working than bringing up children.
Houston added: "Gary says it's easier to lug sand about on a building site or fill in a skip in the rain than look after kids - and that's not what Izzy wants to hear!
"She's very scared as she's thinking that she's going to have to have the baby on her own."
The 36-year-old recently divulged that Izzy will be shaken by the fact her disability increases the chances of a miscarriage.
Watch Izzy reveal her pregnancy to Fiz in tomorrow night's (July 4) episode below: