Some people stay on dating sites even after they have found a significant order out of fear. They worry that something could change for the worse in their relationship and they keep that dating profile active to give them a sense of security.
Oftentimes, this lack of trust in their relationship stems from a previous relationship where they were left emotionally damaged and exposed. They don’t want to be that exposed again.
As long as she is not actively messaging or liking people on the dating site, she is able to excuse her behavior without conscience.
But, in the back of her mind, she knows that there are people looking at her profile and liking it. This makes her feel like she has a security blanket in case something goes wrong in her relationship with you.