We all may have coworkers, friends of friends, and random people from our middle-school debate team on our friend list that our partner wouldn't be able to pick out of a lineup. Many people can't even recognize all of their own Facebook friends, let alone their partner's. You see people commenting on his Facebook wall and sharing inside jokes, and you have no idea who they are.This might show in an increased startle response or irritability if you idly pick up his phone for innocent reasons.

If he seems to be almost compulsive in protecting his phone, closing browser windows, or shielding you from even glimpsing any of his communication, chances are high that he's desperate to keep you from seeing it-probably for a reason.

People who are behaving inappropriately and trying to hide it often have a heightened vigilance against getting caught, and you can see this in their automatic physical behavior.

He is very physically possessive of his phone or iPad.

It's one thing for him to be idly surfing Facebook at 3 a.m.-but if he's trying desperately to hide it from you when you happen to wake up, you have to wonder why. With more and more people sleeping with their smartphones-which evidence shows does not exactly foster healthy sleep patterns-the likelihood of someone having private online communiquГ©s grows as well.

You've awakened to see him on Facebook or on his phone, but he's quick to put it away when he sees you.

But when his online conversations start regularly making their unwanted way into your bedroom late at night, whether by his initiation or the other person's, then you may already be playing second fiddle to another relationship. A wayward text from friends late at night is not necessarily a cause for concern, and some couples actually choose to wind down on their devices, side-by-side. But smartphones have changed all that, and it's gradually grown more acceptable to text someone-and even to expect a responseвЂ“long into traditionally intimate, late-night hours. while the two of you were winding down for bed, you'd probably have been taken aback. Twenty years ago, if a friend or coworker called your partner at 11 p.m.

He gets texts at all hours, including late at night.

But if his digital conversations are frequently taking him away from being present with you, and he makes no effort to bridge that gap, then his attentions, and priorities, may well lie elsewhere. No, you shouldn't expect anyone to be an open book about every single thing they're doing online-boundaries, and a certain amount of privacy, have an important place in any healthy relationship. When your partner is chuckling or otherwise responding emotionally to his device, yet not making any effort to let you in on what's going on in his mind at the moment, it creates a thick wall between you. Compulsive smartphone use can be a constant source of friction within romantic relationships, as one partner feels cut off from the person who is more engaged with a device than with the in-person conversation they're supposed to be having.

He is often lost in thought within his texting conversations and never shares what they're about.

(I use the 'he' pronoun here, but of course, infidelity crosses gender and sexual orientation.) Whether someone's actually having sex outside of the relationship or not, here are six signs that a partner's online activity is threatening to your relationship.

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