In a relationship it becomes more complex then simply a "deal breaker." Abusive relationships, that's a deal breaker. When the other is consistently abusive and unwilling or unable to change I will end that relationship immediately and never look back.
A scene in The Mexican with Julia Roberts (Samantha) and Brad Pitt, (Jerry). Samantha asked Jerry, "I have to ask you a question. It's a good one so think about it. If two people love each other, but they just can't seem to get it together, when do you get to that point of enough is enough? Jerry answered, "never." His answer was immediate, and without a moments hesitation, as if this is an easy one to answer, like even a 2 year old knows the answer to this question.
I agree with Jerry. Never. When two people truly love each other, barring any persistently and consistently abusive behaviors, they will never reach the point of enough is enough.
I think in today's day and age many people are like a kid in a candy store with $5.00 in their pocket, their eyes are wide with excitement and don't know where to begin and grab everything they can for their $5.00. When they've reached the end of their money, and sitting with a big bag of candy they begin thinking, "if they only had $5.00 more they would have bought this or that." Instead of being satisfied with their choices, they are looking for more.
Many people handle relationships today in much the same way. Lonely men and women pray at night to meet that one special person they believe God has reserved for them. Then one day they meet, almost love at first sight, they agree together they are a match made in heaven.
Shortly after they begin to notice little things that start to annoy them. Things like he talks too much, or says the wrongs things, or forgets where his keys are. She brushes her hair too much, or uses too much or too little makeup, or any number of little insignificant things.
Then doubt starts to set in. They begin to take notice the other people available to them and start to neglect the person they have in their life now. Before too long they are nit-picking every little thing, tearing each other down verbally and mentally. They begin inventing problems out of thin air, and their perfect relationship goes from one battle to the next.
In my opinion if two people truly love each other and are committed they share each others successes, comfort each other when dreams and plans fail. They will encounter all joys, trials and obstacles that come their way together and never allow little things to get in the way. Nothing would ever be a "deal breaker."
For me love relationships are not simply a "deal, or agreement" it's an eternal vow of the highest order made between two people with a bond stronger than blood, more binding than words alone, and more permanent then ink on paper, it is a vow made with love.