Rights of the wife when she discovers that her husband is flirting on social media

Hello,

My friend is from eastern Europe married to Emirati. They have 2 small daughters ages 2 and 12 months.

She has caught her husband many times talking to women on social media and he hides his social media accounts from her and has blocked her.

He also always hides his phone from her and he always goes away for the weekends without telling her where, but she has no witness and is alone.

What can she do about this?