Is it obligatory to renew the marriage contract after doubting the religion and then returning to faith?

If the doubt is merely a whisper (waswasa) that you dislike and repel, then it does not harm you. In fact, your dislike of it is an evidence of the sincerity of your faith: "That is pure faith," and "Those are true faith." This does not affect the religion of its owner nor the marriage contract. However, if the doubt is continuous and you do not dislike it, then this is disbelief that expels one from the fold of Islam, and a marriage contract with a Muslim woman is not valid with it. After repentance, it is necessary to renew the marriage contract.