Is it obligatory to please one's mother by refraining from marrying the one you love after an unfortunate event has occurred, or is it obligatory to marry and present everyone with a fait accompli to please Allah?

Obeying one's parents takes precedence over marrying a specific woman. However, if one fears falling into temptation (fitna) due to his love for her, he is permitted to marry her while striving to gain his parents' approval. It is not permissible to marry an adulteress unless she has repented and her womb has been cleared (istibra'). Repentance must fulfill its conditions. If marriage is not feasible, then he should sever his relationship with her and beware of being in seclusion with her.