It may feel easier short term to bury suspicion with denial (men being cheated on do this too). It's easier to question our own motives for suspicion. Have you ever had a trusted relative or friend visit you, only to discover later that some money or a possession is gone? Do you suddnely think they stole from you and accuse them, or do you tend to believe (at first) that the money/possession was misplaced? No one wants to believe someone they've invested trust in can easily lie and conceal things from them. No one wants to feel that the person they love doesn't put them first in their life.