Unless there are many other strong, positive aspects to your relationship that strengthen a feeling of support and understanding between you, this aspect could be the deal-breaker. The problem is a certain level of natural competition and irritation that occurs when you're together: Your lover just gets under your skin on a variety of levels. The energy that is created when you're in one another's company runs hot and high; it stimulates quite a powerful physical attraction between you, and make you downright hungry for this person, and vice versa.
The likelihood is also that you are a couple who argues passionately and then kisses and makes up even more passionately. This can be quite exciting, but it's not a great influence for a long-term bond. It's hard to sustain a feeling of trust and support with someone who seems to challenge you at every turn, and this is how you see your partner -- regardless of their good intentions. Your senses of your own individuality are at war here; any disagreement feels to you like an attack on who you are as a person. You fight to defend yourself and may not even stop to consider whether this is a battle that really needs to be fought. In order to avoid the pointless flare-ups that could become commonplace between you, you both need a highly positive attitude -- or simple acceptance that you have a hard time staying calm when you're together.