U hv mentioned that he is ur collegue, so it should be easy to find his background and whereabouts to a clarity about his identity. First try to gather info about his identity and feel whether he is worth or not for you.

Firstly find out the truth. If that lady is not his wife , then asses the relationship axis of your colleague with his family. Do you foresee a problem living in the joint family? if that is the case? How much committed is the guy in this relationship...Asses this and take a decision.

Hi, I can understand that you are feeling confused about the whole thing. Ask your colleague to introduce you to his family. If his intentions are right, then he will do so. Also find out from his friends and other colleagues in your office and about his background. You might get an idea about it. This is a pretty sensitive issue and you have to deal with it patiently. You have already gone through divorce and whatever decision you take this time, should not let you down again. All the best.