Bro I'm a father of 3 children.

Eldest is 7 going 8 y.o. this Aug -- a boy, 2nd and 3rd are daughters, 6 and 4.

When the youngest was still an infant, the middle child is jealous of her. What I tried to do that time is show more affection to her to acknowledge her feelings of jealousy and insecurity....and because my son is her kalaro at home...naging madali for her to adjust to the new family member...then when the youngest was growing up and becoming more conscious of attention...she became the centerpiece because the two older kids were magkakampi. When the 4 of us play together, magkakampi yung 2 older kids and kakampi ko yung youngest. Sibling rivalry is normal and you don't have to feel guilty if that exists. What you need to remember is that every kid is unique so you have to treat him/her the best way it is for him or her...but most of all, the kids just need more time from us parents. An advice given in one of the parenting seminars is to spend time with each kid separate from each other...I am trying that soon too.

Good luck with your parenting.