Actress Shar Jackson is determined ex-boyfriend KEVIN FEDERLINE will honour his responsibilities as a father to their two children. Jackson was prepared to accept Federline's marriage to pop star Britney Spears in 2004, but she won't let him favour the two kids he has had with Spears over her the two they had during their relationship. She tells gossip site The Scoop, "As far as I was concerned, I was OK that the relationship ended, but the family breaking up is something painful. "And honestly I didn't let it happen. Now in the beginning it was rough, because he was overseas, so I really didn't have much control over there. "But when he came back home, I told him, 'Kevin, I'm not going to let you be a convenient father, when it's convenient for you. If you are going to be part of these kids' lives, then you're going to be a part. If not, then you're not.'" Jackson adds that her children see Spears and her two children with Federline as ''extended family'', but she has not met one-year-old Sean Preston and new born SUTTON PIERCE because, she says, "I keep my distance".