The foundation they once held as stable and solid is gone, and life is no longer routine. Stepparents often find themselves the brunt of these kids' frustrations and fears. This is uncharted water for everyone, so the adults end up playing their role without the advantage of experience. Be reassured, you are not alone. Millions of people are desperately trying to find their footing in this new position.
Kids can sense a public relations job a mile away.
Let them draw closer at their own pace. Trying to change yourself to suit every situation will wear you out physically and emotionally, and it offers only temporary solutions, at best. Life is rarely like a sit-com. Identify and respect their boundaries, and expect them to do likewise. Don't accept manipulation.