In spite of he was rich, he lived a relatively simple life.
In spite of being rich, he lived a relatively simple life.
In spite of the fact that he was rich, he lived a relatively simple life.
Use in spite of + noun/-ing: ‘In spite of the rain, we went out.’ ‘In spite of feeling tired, she continued working.’
Do not use in spite of directly before subject + verb. Before a complete clause, use in spite of the fact that: ‘In spite of the fact that he was rich, he lived a relatively simple life.’
Write in spite of as three separate words.
See ALTHOUGH