Is it permissible for a newly married husband to consummate his marriage with his wife while he has unfulfilled prayers or fasts, and what should a person do who has recently repented from abandoning prayer and fasting, and has many missed obligations from before the marriage?

The scholars have not stated that it is forbidden for a newlywed man to have intercourse with his wife before making up the missed prayers that are due from him. This person must repent to Allah, seek His forgiveness, and do many good deeds. He must also make up all the abandoned prayers immediately if he knows their number. If he does not know their exact number, he must continue to make them up until he is reasonably certain that he has fulfilled his obligation.