The 21-year-old singer - who has been dating the 'Twilight' actress since the summer - has developed strong feelings for the screen beauty, and though pals insist The Feeling is mutual, they still believe Joe will be hit harder if they eventually go their separate ways,
One pal said: "They both are still in the trying-to-impress-each-other phase. If I were to say who wears the pants, Ashley certainly does but Joe doesn't realise how much power he actually has in the relationship. She likes him just as much as he likes her, but I think he would submit more easily to her and take it harder if they broke up."
Despite spending the summer together, the couple face separation in the coming months, with Joe away on tour and Ashley, 24, scheduled to start filming the fourth instalment of the vampire franchise, 'The Twilight Saga: Breaking Dawn' in November.
However, the pair have already begun comparing schedules in a bid to work out the maximum time they can spend together.
The source added to website HollywoodLife.com: "They have equally expressed how they are going to deal with each other's schedules with Twilight and the Jonas Brothers South American tour, which actually ends rather early in November, so Joe will have plenty of time to visit her. They are having a fun time with each other right now."
The pal explained: "Joe is head over heels for Ashley. He thinks she is down-to-earth and absolutely beautiful. He hasn't been this into a girl in a long time."