@jjrox1413,
Given that his former girlfriend probably thought he was cheating on her with you, I'd recommend letting this go.
People are allowed to have prior relationships. People are allowed to date a few people at the same time. It is not a big deal in the overall picture of life.
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He chose to marry you - to make a life with you.
Try to focus on that.
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If you are letting this get in the way of your marriage, you may need to consider some professional help.