My 7 year old daughter has very recently become very affectionate with her soon to be step dad. What could cause this? She doesn't see her dad often, but calls him daily. Could it be as simple as she see's me hugging or kissing my boyfriend, so she assumes she should do the same? She seems to always be asking him for hugs or cuddles or trying to kiss him on the cheek. She isn't overly affectionate when it is just the 2 of us at home, only when he is around recently.
Seems to me that your daughter is mimicing your behavior as she begins to explore her sexualtiy. It's only natural that she would model her behavior after your own. While kissing on the cheek and cuddles appear innocent enough, there are times when they are appropriate and times when they are not. When someone leaves (for school or work), a kiss on the cheek or a hug goodbye is ok. When you say goodnight, she probably kisses you (or you her). But to just clammor up onto the couch and want to kiss and hug is not, what I would think of as, typical behavior.
It might be a good idea to discuss the relationship you share with your boyfriend (privately with her). Ask her opinion, using specific questions, about him, about her, her father, about the four of you and how the relationships fit together dynamically. Address any concerns she might have. And let her know that if she ever has any questions, that you will listen and answer as honestly as you can.
I expect this goes without saying, but... Guide her through this in a compasionate and loving manner. Be considerate of not hurting her feelings. She doesn't realize that she wants your boyfriend to love her, too. She thinks that getting that love is accomplished by hugs and kisses and cuddles as opposed to understanding that those are things that adults do after feelings develop (not before). It's likely that she doesn't really understand that there are different ways to love.
While I was able to find plenty of material one the developmental stages of sexuality, there was nothing in regarding sexuality and child-adult relationships. Quite probably an indication of our current social norms. More than a few articles indicated that sexuality was an involved process that starts at birth and continues throughout our lives. This passage was, perhaps, the best:
Sexual development is a multidimensional process, intimately linked to the basic human needs of being liked and accepted, displaying and receiving affection, feeling valued and attractive, and sharing thoughts and feelings. It not only involves anatomic and physiologic functioning, but it also relates to sexual knowledge, beliefs, attitudes, and values. Sexuality should be considered in a context that extends beyond genital sex to include gender-role socialization, physical maturation and body image, social relationships, and future social aspirations. Sexuality of Children and Adolescents With Developmental Disabilities