These couples had not reported a decline in their relationship within the first six months of marriage; in fact, narcissists are often viewed positively by partners at the beginning of a relationship — and narcissists themselves may view a new relationship as an opportunity for ego validation. Over time, however, the narcissist's low commitment, self-centeredness and antagonism may chip away at relationship satisfaction.
Similarly, a narcissist's selfie-posting may be viewed as attractive or endearing in the early stages of a relationship, but may become increasingly irritating as the relationship progresses.
So it's not yet possible to conclusively establish whether posting selfies in itself damages relationships or whether selfie-posting and problems in relationships are symptomatic of an underlying trait such as narcissism. Further research may prove the link, but until then, you might want to consider not just the message your obsessive posting of selfies gives to others, but also the potential damage it could cause to your love life.