Modigliani was drawn the bohemian life which drew him to the drugs and seedier side of life. Through his studies he developed the philosophy that creativity was enhanced by disorder and rebellion. The drugs, alcohol and illness sapped the strength from Modigliani and eventually he gave up carving in stone for the physically easier occupation of painting portraits. Yet, one can see the depth of form in his paintings that came from his 3-D work.
Modigliani and Picasso were friends and rivals in Paris. It seems that both artists reflect an influence of each other by painting in a cubistic style that for a time shares characteristics. Picasso owned several of Modigliani's paintings. However, he seemed to feel that Modigliani was exaggerating behaviors to enhance his image. At one point he commented, 'It's odd but you never see Modigliani drunk anywhere but at the corners of the boulevard Montmartre and the boulevard Raspail.' http://www.artchive.com/artchive/M/modigliani.html
Modigliani produced great quantities of work which lends credibility to Picasso's comment. I don't think it's possible to create as many works of art as Amedeo did and drink all the time.
In the early years of WWI Modigliani became involved with South African writer Beatrice Hastings. She was somewhat successful and was able to provide a living for Modigliani. Even so, the relationship did not go well. It was marred by excessive drinking and abuse. At one point Modigliani threw Beatrice out a window.
He had numerous love affairs but most did not last long. However, these affairs did produce beautiful paintings that have in time made Modigliani a famous Modern Art Master and added to his image as a Great Latin Lover.