I am not new to guitar by any means but this is something I have never really thought much about. Sometimes, when I bend and release a note, I will hit the string next to the string I am bending and cause that string to play open. Like if I were bending the G string up (towards the low E), I would hit the D string and cause an open note on the D string to ring when I return to the G string's original pitch. Any tips?
My Gear:
Fender American Deluxe Stratocaster
Epiphone Sheraton II
Fender Blues Deluxe Reissue
Teese RMC Picture Wah
MXR Carbon Copy
Keeley Modded TS9
Korg Pitchblack
Schecter Omen 6
Dean Performer Acoustic

play with your fingers more vertical, and hit the string with the tip of your finger.this minimizes how much of your finger is on the guitar and prevents any space issues,like hitting other strings
I guess just practice the way you release the bend and pay close attention to the problem, then try to correct it before it happens again.
I suggest the exact opposite of athlete1's method (sorry bro, nothing personal).

Instead make your fingers big and flat, so that they not only fret the note on the G string but also touch the D string. Without bending, nothing but a muffled thud should come out when you pluck the D. Now, when you bend, you'll push the D string along too, but unless you completely let go (making an open G ring out), returning to the original pitch should still keep the D muted and you should only hear the notes you want.