Thanks for the query.
Depo can lead to side effects like irregular periods
And as the progesterone
can alter the cervical mucus secretion, that may be one reason for altered vaginal discharge
If you have associated features like itching etc, there is possibility of vaginal infection
And infection can spread from one partner to other.
So you once consult gynecologist, get examined to find out the exact cause of the problem and take treatment accordingly.
For more details you can ask me directly through the premium forum.