If there are things you'd like him to do to let you know you are loved as much, tell him. Maybe he just knows what she needs because she is so familiar to him. He might not realize that you're feeling like you get less from him than she does.
Are you familiar with the book, "Five Love Languages?" Here, you can take an assessment test to see what "language" you need to receive indications of someone's love. The choices are Words of Affirmation, Quality Time, Receiving Gifts, Acts of Service, and Physical Touch: