Ben Affleck Enjoys Motorcycle Ride With Son While J Lo Vacations in Italy

Jennifer Lopez is out in Italy on a boat -- and Ben Affleck is here in Cali on a motorcycle ... hammering home the fact that they're worlds apart these days.

The actor was photographed enjoying some quality time with his son, Samuel, Wednesday ... in L.A. ... riding around on a motorbike. The kid seemed to be having a good time on the cruise about town ... smiling while clinging to his A-list dad's back.

Of course, J Lo was nowhere in sight ... as she was spotted catching some rays in Positano earlier Wednesday ... hanging out with some friends of hers, sans family.

Despite stepping out together for family events of late, Ben and Jen aren't currently living together ... with the famous couple trying to unload their Beverly Hills home under the radar -- just a year after scooping it up for $60 million.

Right now, the Oscar winner is crashing at a rental in Brentwood ... which is not far from where his kids live with Jen G. As for Jen ... she's been seen house hunting out in L.A. herself. And, based on her whereabouts this week ... it seems she needs some alone time.