Complex sentence: His personal life was also in a crisis, his affair with Léda became more and more of a burden for him; with Ady becoming a famous poet Léda lost her leading role in the relationship.
Split into simpler sentences: His personal life was also in a crisis, his affair with Léda became more and more of a burden for him. As Ady become a prominent poet, Léda lost her leading role in the relationship.