We can imagine who she's envisioning when she hits the bag!

Jennifer Garner showed off her perfectly sculpted arms at boxing class this morning, and the actress doesn't let a day go by without squeezing in a workout. We all know exercise is a good stress reliever, and she's had more than her fair share of that lately!

Now that Ben Affleck has completed his treatment in rehab, he's back at home and back to having sleepovers with Playboy model girlfriend Shauna Sexton. His ex isn't too thrilled with his new romance, but she's trying to stay out of it and let his counselors and sober coaches steer him in the right direction.

A source tells X17:
    "Jen would obviously prefer if Shauna wasn't in the picture. It's not a jealousy thing at all, she just wishes Ben would focus on his sobriety, his kids, and his career and stop looking for love in all the wrong places. She thinks he's incapable of being alone, and that he has to learn how to be OK with himself before he dives into a relationship, or else he puts himself in danger of relapsing."

She's the perfect example of how to conduct yourself after a painful divorce, as she decided to focus on motherhood and her health, and give herself some time to just be single.