It's usual to think of other women whilst being in a relationship trust me a high percentage of boy are thinking of other girls even when they are with their partner.
But now comes the part whether you stay or go. Tbh that is the easiest part, just sit back and think for a moment
does your present partner loves being around you? If yes then stay,
does your current partner makes good healthy food for you? If yes then stay,
does your current partner loves you for your flaw? If yes stay, and last part
does your current partner ignores your mistakes? If yes then stay.
A good bond is very easy to break but when you build a healthy relationship it takes some time. Because there are two people trying to build a better world for each other.
Hope it helps you to choose or not to choose. Additionally I wish you a happy and good life whoever you choose to be with.