^^This.

People have different sexual and emotional needs and if they are not being met they will look elsewhere for it. Sometimes there is nothing you can do. For example, some women like to be held/cuddled at night and some dont. She's not going to tell you what she wants because women arent used to speaking their mind.

You should examine your entire relationship and figure out if you are in a reciprocal relationship where both parties are giving and receiving love equally?? From your post, it looks like you do alot for her.

Does she return your love/affection?? Do you feel like she needs you more than she loves you?