Leanne Bourne , from Essex , discovered her partner was having an affair . Was horrified when the other woman turned out to be her sister Larissa . Larissa even gave birth to Steve 's child in August 2011 . Had initially claimed that she did n't know who the father was . More than three years on , sisters are still struggling to overcome the affair . Leanne and Larissa appear on My Sister Had My Boyfriend 's Baby - and Other Betrayals , This Morning at 10pm on Channel 5 .
Leanne Bourne , from Essex , discovered her partner was having an affair . Was horrified when the other woman turned out to be her sister Larissa . Larissa even gave birth to Steve 's child in August 2011 . Had initially claimed that she did n't know who the father was . More than three years on , sisters are still struggling to overcome the affair . Leanne and Larissa appear on My Sister Had My Boyfriend 's Baby - and Other Betrayals , tonight at 10pm on Channel 5 .