You can try victim level police admin data. Many help organisations can provide a sex break down of clients. Crime surveys are useful sources for underreported crimes such as sexual violence.
This varies widely by region. Most generic victim services will provide support to men, but there are many structural barriers for why men may not disclose violence and seek support. Beyond reasons within masculinities theory about hegemonic masculinity and help-seeking behaviours, many men have the perception that victim services are for women, or they do not know that other men have similar experiences. There are some services like the Centre for Men & Families in Toronto that have specialized supports and groups for men who experience partner violence.