keep a tight rein on sb

to keep a tight rein on sb (to control someone or something carefully) — держать в ежовых рукавицах; осуществлять строгий контроль

Example 1: Our parents always kept us on a pretty tight rein.(CIDI)
Example 2: She kept a tight rein on her husband.

see also
[keep sb on a short leash]
[keep sb on their toes]
[run a tight ship]