I do understand that you may have come across certain cases of premarital and post marital affairs but that does not mean every one has it. You can not avoid driving; thinking that so many people had an accident in past. If you find suitable match then you may think of getting married and once you decide on that line then stop thinking about her past and never try to dig it.
Your impatience seems to be a part of your personality and rest of symptoms may be because of Depression, which may be secondary to your emotional problem. Decide your priorities and plan your future action accordingly.