I would posit that you really are "looking for someone". Someone special, someone who will love you as much as you love him/her. We all spend a lot of energy and time building castles in the air...you know, those daydreams of a perfect mate in a perfect place. Sort of a Club Med with movie stars who are really nice, loving people!
The disaster just ending is even more of an incentive to move on into something better.
So, that's the why...the rest is not as easy.
There are a lot of good reasons to say no to any and all workplace attachments. I've never seen any of them last and when they disintegrate, they create a lot of casualties. Someone usually leaves to find a job that doesn't have a the 'ex' present!
Office 'love' is usually not love at all, IMHO! It tends to be a lot of things, but real love just gets left out. Too often one is the ladder and the other is the climber. As soon as the climber gets to the next level, it is time to start looking for another ladder.
This is especially disastrous when the object of your love is your supervisor or somewhere in the ladder above you. You may wind up scrued and dumped, looking for a new job. I worked for a ball-breaker like that once! Never again!
So, the moral is simple: Looking for love in all the wrong places is a sure way to never find it.
Work hard at your new job and play hard somewhere else.