It's very hard to think straight when your lover's in the doghouse. It's even more difficult to think straight when a new, uncomplicated suitor starts flattering you with offers of romance, flashing that alluring 'get out of jail' card before your boyfriend-weary eyes. But what's hardest of all is deciding when it's time to call it quits on a relationship that has grown sour - or even deciding when a relationship HAS grown sour and isn't just passing through one of those phases that must be endured for the partnership to grow.
It takes great wisdom and maturity to be able to sift through the evidence, weigh up the merits of an on-going relationship, counter-balance these with the promise of a fresh romance, make allowance for the possibility of future regret, and finally come to a good decision. And it takes a great deal of self-awareness too. We all try to save ourselves from anguish when making big decisions in life, but sometimes it's important to accept there'll be pain in the short-term in order for us to reap the rewards of long-term gain. So when your thoughts turn to staying with your boyfriend, is it because you really WANT to wake up with him tomorrow or because you're appalled at the prospect of breaking up and maybe terrified of the unknown? Please don't stay with him to save yourself from the agony of breaking up, or out of habit, or because you hate failure, or through some misplaced sense of loyalty. Just because a year ago you decided it was right for you to be with this guy, doesn't mean the partnership must endure for the rest of your life.
If you've given it your best shot and the arguments are going around in circles, maybe it IS time to break up. But if, on the other hand, your love for this guy runs deep and you can visualise a way out of your current black hole (perhaps your boyfriend senses the presence of a rival and this is at the root of his contrariness), then try to resist your colleague's advances.
Though it doesn't always seem to be the case, we CAN brace ourselves against temptation and stop those loving feelings from running wild. But if this is the path you decide to follow, you'll need to be straight with the guy, explaining that you want to give your relationship a fresh start and that he needs to give you space to allow this to happen. A guy of honour will know when to back off. Good luck.