wondering if you've even watched the show. dean went to lisa and ben because sam wanted him to have a normal life. dean went to lisa and ben broken and miserable, and he stayed that way the whole time, making lisa miserable too in the process. she stated herself that she wanted something she couldn't have. they were not a match, and dean chose to erase her memory for a reason. he'd never go back to her after what he did. plus, she's probably found someone to spend her life with after dean erased her memory let's be for real. that's such a bad take guys!!