In Les Misérables, the father of Fantine’s baby, Cosette, is a wealthy young man named Tholomyes. Tholomyes and Fantine were in a romantic relationship, and during their time together, Fantine became pregnant. However, after the birth of Cosette, Tholomyes abandoned Fantine, leaving her to face the struggles of raising their child alone.
Fantine’s circumstances become increasingly dire as she attempts to provide for Cosette. Driven by desperation, she ultimately turns to a life of hardship and sacrifice for her daughter’s future. This part of the story highlights the themes of love, abandonment, and the societal challenges faced by women during that time.