I think that what you're talking about is retaining your independence and trying not to be jealous of other women that he might meet, particularly in his former workplace.
Of course it’s possible not to worry about something like this, and to retain your independence.
But, the only place that you can do this, is in your head. You say he’s a ‘good guy’, well act as if he his. Believe it! The more that you believe it the less you will be concerned about his activities. He isn’t Tiger Woods is he?
So, tell yourself that he’s with you. Continue to enjoy and lead your life. Continue to enjoy and have a relationship with him.
Don’t let your thoughts and doubts and projections of doom trip you over. If he’s a good guy – treat him like one and believe that he is one.
Remember, your thoughts are very good at manifesting what you want. If you want him to be unfaithful then he may well turn out to be. However, if you want him to be loyal and trustworthy, then that is what you’ll create.