The DDC is quite reliable. They often do clean-up for other labs that have made mistakes. If you can't keep from obsessing, you could get a different test done at whatever local lab is used by the family courts in your area, with your boyfriend. But no amount of DNA tests can put psychological reasons (guilt, regret, shame or wishful thinking) to rest. Only you can decide that you are willing to accept what the dates and the tests are telling you.
I would also like to mention she doesn't look like the rebound guy anymore.
It's just some of her features are like his!!!