The number one issue is what is best for the three children or at minimum what environment is best for them. This man is their father even if not your husband. In many states, a long time relationship is established by common law marriage- at least legally. It may hurt that marriage is not an offer on the table but you basically trained him that it didn’t have to be a deal maker.
As to Bill, it is probably fantasy to go so far back intime to a casual relationship and think that this past could be the basis for a sound new relationship. Best is to do right by your children and work at your exsiting relationship and over time see if marriage can be in the cards. But if you do not love your man, then you need to consider leaving and those consequences and establish who you are as a person before going into a new relationship confused at best and immature at worst.
