It's not that she didn't trust her husband but she just couldn't bring herself to risk him divorcing her, and thus her losing her family, as soon as he found out. It was like an end of the world situation for her, and it didn't help that the villain would further reinforce those fears and sabotage any attempt to reach out to her husband. There actually is an option to not forgive Misaki and abandon her and you can choose that option but the game makes it clear that that is a stupid move that the writers and the MC point out when he meets her again in 20 years. It demonstrated very clearly that she had loved the MC all along, and never wanted anyone else to be her husband, and was capable of overcoming the corruption and sexual addiction unlike almost every other NTR heroine. I understand her POV in a way since I experienced something somewhat similar, being forced to lie to a parent for years because of being scared to death of the consequences of them finding out the truth about your grades ;_;