so im trying to find a title of a romance novel. here is what i know about the plot-hopefuly someone could identify it for me

- a man has a child by a coloured women & then moves to england to raise it
- he meets a young women on her birthday coming out of a library and knocks her books out of her hands by accident
- she is studying butterflies
- the women who gave him the child also gave him a necklace with a lock of hair in i-supposedly protecting him from people who don't have his best interest at heart
- the butterfly scienctist and him are planning to get married, but a prior mistress gets hold of his necklace and changes the hair-of course he falls for the mistress,losing all memory of who he was before
- the butterfly scientist deals with the sudden change, and when handing back the ring he gave she took the necklace and removed the mistress' hair, of course he gets his memory back and things move on in their usual sense

if anyone can help with the title that would be great!