Hmm, I felt the same way about our first born. I really struggled with bonding with him, took about 6 months if the truth be told. One of the worst expereinces of my life, I remember thinking, "What the hell have I done? I've got a lifetime of feeling 'Meh' about my own son". There's a lot of pressure to feel that epiphany moment when you first hold your offspring, but in my experience it took a few months before that moment arrived.
Having said that, in retrospect I should've pushed myself a lot more out of my comfort zone, which is what I would suggest with your DP. Make him change a few more nappies, hold her more, feed her (if you bottle or express BF), play with her. I did help out DW a lot more than your DP seems to, so maybe you need to get him to step up a bit? The question I suppose is how do you do that.
Would you be comfortable leaving him and her alone for a bit, just the two of them? When someones watching it always feels a bit weird to me because I expect them to pick up on any mistakes or discomfort I feel. I appreciate she's still very young, but it could be an option?
Alternnatively, it could just be time. It's still very early days.