I work with cons and ex-cons every week. I would be careful. Crime and prison teach you to be a very good liar and it's an addiction that is hard to turn off. Convicts lose control of their life to the legal system, and lying and manipulation is something they perfect in order to feel they have some sense of control. Even the best intentioned guys I've worked with have/will lie to me and others without so much as a blink.
So anyway, God forgives, but if you want to date a convict, be careful. I wouldn't recommend dating a con unless he's been out of prison at least 3-5 years and has shown him self to be stable, trustworthy, and reformed.
Hope this helps.