Best advice ever,
@Biffer2z mate if u love this girl and she loves u, she will understand. Tell her that ure doing this because u care more about her than that shitty drug but for the moment u need the bupe. Shell eventually find out anyway man. So it's better if you tell her than if she finds out from someone else or she finds ur stuff, etc shit like that.
Mate plz, I was in the exact same position but I didn't tell her, one day I was too fkn sick and she found Me shooting up in the bathroom. Needless to say the bomb exploded she told everyone in my house, I had to go to a 2 month rehab and when I came out she had cheated on me. Things were never the same. So plz man, think very well whst you're doing. Don't fuck up like I did.