The female libido remains so mysterious! There's been a lot of research into a "little blue pill" for women, but it remains elusive and I think that's at least partly because women's sexual response can be so complex and involve such an interplay of physical and emotional factors.
A friend of mine was really helped by a book called "Reclaiming Desire" that walked her through some exercises to address all the different possible causes of a lack of libido. She had to start taking better care of herself physically and emotionally before she got anywhere. It also has good sections on motherhood and menopause - I haven't experienced either of those personally, but she has. With pregnancy and breastfeeding, she says you really get the one-two punch of hormonal changes plus exhaustion. Just understanding what was going on physically, she said, helped her husband be more understanding.