Complex sentence: When his aunt learned of his behaviour towards Miss Williams and disinherited him, he felt he must marry for money rather than love, but he elicits Elinor's pity because his choice has made him unhappy.
Split into simpler sentences: When his aunt learned of his behaviour towards Miss Williams and disinherited him, he felt he had to marry for money rather than love. But he elicits Elinor's pity because his choice has made him unhappy.