U might get used to the feeling of having a big dick in you but I can assure you the vagina isn't becoming bigger. Every scientific article on the subject says pretty much this:
"Your vagina is elastic. This means it can stretch to accommodate things coming in (think: a penis or sex toy) or going out (think: a baby). But it won’t take long for your vagina to snap back to its previous shape.
Your vagina may become slightly looser as you age or have children, but overall, the muscles expand and retract just like an accordion or a rubber band."
Who or how often u have sex with has no impact on your tightness.