Complex sentence: It was then that Sonni turned up alive to Josh's shock and after a bitter argument in the Country Club, Josh definitely left Reva and remarried Sonni out of duty, while Reva became involved with Alan.
Split into simpler sentences: It was then that Sonni turned up, alive, to Josh's shock. After a bitter argument at the Country Club, Josh left Reva and remarried Sonni out of duty, while Reva became involved with Alan.