Because you are highly responsive to her needs! She knows that you recognize, listen and respond to her, so her "communications" to you are much more frequent. Not to say that your husband is not responsive, but probably 90% of the time it's YOU...you are her main caregiver, her strongest attachment. She trusts you and has no qualms abut letting you what's on her mind because she knows you'll understand and respond.

We are in a similar situation with my daughter. I am with my DD most of the time and work about 1 day a week when my DH takes care of her. Both he and my mom have remarked on how she is more needy with me. I would agree with what the previous poster said and add that I have read, this is total paraphrasing..
Our little ones kind of store up their emotional needs when they are cared for by someone other than their primary attached person. Then they whine or are clingy or demanding or whatever to get their emotional cups filled back up.
If it isn't a problem for you, I'd say, this seems like a pretty common way of interacting. If it is draining you, by all means, set some boundaries. Get dad or others to help you get breaks, or pay attention to how you are responding to your daughter. My DD talks a lot more around my DH. I think I anticipate what she needs or is thinking about, so she doesn't have to talk. When I try to get her to use her words, she get shy or frustrated, like she is saying "you know what I want."
One thing I do need to learn to back off on is, I know what she wants, and my husband doesn't get her communication as quickly, so I step in. This just reinforces her coming to me instead of learning to problem solve with him.
Anyway, I'm curious what your thoughts are & I think it is really normal behavior for you and your daughter. She is lucky to have such a responsive Mama!