One of Sagittarius' best and worst qualities is their need for freedom. Your sign doesn't do well with boundaries, ultimatums or attempts to control you, especially in love. Your generous heart is always open and willing to welcome a partner in crime.
But when someone tries to throw a rope around your neck, it's over before it even began. Sagittarians are so quick to be drawn to someone that they may have trouble with fidelity from time to time, preferring to play the field for as long as possible. Sometimes they cross boundaries into the non-platonic realm before they realize it.
It's not totally out of your control, though. You don't want to hurt or disappoint anyone, so instead of letting your eyes wander, why not wander with your dating partner on a spontaneous travel experience?