Distressed Matt Damon fears recovering boozer Ben Affleck may fall off the wagon amid his crumbling two-year marriage to Jennifer Lopez, RadarOnline.com has learned from insiders. A source claimed the frantic filmmaker is pulling together his Batman buddy’s nearest and dearest to stage an intervention. According to tipsters, Damon is growing increasingly concerned for his lifelong pal as jet-setting J Lo, 54, appears to be moving on without him. “Matt wants those closest to Ben to remind him he is loved and supported — and better off without Jennifer,” an insider alleged. “Everyone is rallying…