As time goes on, you stop spending as much time with your friends and family, your habit of forgetting to text people back worsens and, before you know it, you’re living a hermit's existence - albeit with another person in tow.
For a period of time, you’re happy to let that happen. But what starts off as blissful captivity soon turns to isolation. And the price for this can be high.
In some cases, this failure to keep up appearances with friends and family can be detrimental to a person's health. A study of 222 individuals from 2015 found people with smaller social circles to be at a greater risk of early mortality than those who drink to excess or suffer from obesity.
Similarly, a previous study by Harvard researchers discovered that lonely people have a higher risk of early mortality than those who have lots of friends.
"In short, loneliness kills," says Madeleine Mason, psychology expert and co-founder of dating expert company PassionSmiths.
"Having a network of high quality relationships is likely to mitigate the risk of health issues. However, while it is easy to simply demand people nurture relationships outside of their romantic one, it's easier said than done."
Barbara Bloomfield is a relationships counsellor for Relate. She says that the issue of couples isolating themselves from family members and friends is a problem she often comes across. This is known as a ‘babes in the woods’ relationship, where a couple will live inside their own circle of trust and hide away from the “scary world”.
"In some cases, relationships like this can work well in terms of companionship," Bloomfield notes, "as in these types of relationships, people will thrive off one another’s company."
But relying heavily on one person for social interaction can also, over time, lead to the demise of a relationship.
Not only can it lead to a depleted sex life, says Bloomsfield, but it can also result in unhappiness.
“To have exciting relationships, you need excitement,” she says. “There’s little excitement in a relationship where you are together all of the time.
“Becoming isolated from other people is also never good. You can be more likely to feel depressed and the longer it goes on, the more dreary life can become."
This is something that Katie Cooper, 23, knows all too well. She was 21 when she entered a stifling relationship and, over a period of two years, her network of friends and family slowly dwindled to the point where she felt incredibly isolated.
Her boyfriend explicitly stated that he didn’t want to meet her family, which made things harder for Cooper as she had to share her time between the two - and, being young and in love, her boyfriend was often the priority.
“You end up relying on that one person for social interaction,” she says.
"He would go out a lot and I’d be up until 2am waiting for him to come home. It’s not nice when you’re 23 to be in such an intense relationship. It’s not healthy and I’d become very obsessive, which isn’t what I’m really like."
Just before Christmas in 2015, Cooper's world fell apart when her boyfriend unexpectedly split up with her. In the aftermath, she realised just how much she'd neglected her relationships with friends and family.
Not knowing how best to reconnect with the people she loved, Cooper channelled a lot of her energy into working and disappeared from social media - the last means for her friends to keep tabs on her - altogether. It was then that three of her friends detected her absence and reached out.
“I needed people there for me,” she explains. “My friends could see from me not being active on social media that I needed help and they reached out. It’s weird but a lot of people didn’t even know we’d broken up.”
Cooper was so thankful to her friends for reaching out that she sent them flowers as a way of making amends.
Looking back, she says she hugely regrets not keeping up appearances with friends and family throughout her relationship, and believes this is something that would definitely be different in future.
"I'm not looking for another relationship, but when I do I'd like to meet someone who gets on well with my friends and family, so we could all spend time together," she says. "I think that's really important."
In cases like Cooper's, it can be difficult to know where to begin in terms of rebuilding the friendships you've neglected.
Madeleine Mason has some words of advice for where to start. "Most friends are forgiving when it comes to reengaging friendship," she explains.
"Depending on the nature of the 'breakdown' and depth of the relationship prior to 'disappearing off the radar', a simple acknowledgment and apology of one's behaviour is often suffice to reconnect with someone."
When a person's partner dies unexpectedly, it can be even more difficult to rekindle relationships. Particularly as you are left to navigate your grief and deal with loneliness.
In 2006, Georgia Elms, then 38, lost her husband Jon suddenly to meningitis. The day after he died, she found out she was pregnant with their second daughter.
Elms, who is now chairperson for Widowed And Young (WAY), says that a lot of couples naturally become quite insular when they have children. And, after your partner dies, lack of childcare can make it even more difficult to get out there and socialise.
"You can't go out much and, even when you can, you're too knackered," she says. "Then, when your partner dies, you struggle to find childcare so you can't go out with your friends.
"Sometimes your friends don't invite you to gatherings anyway because you're not part of a couple. And some friends don't want a single woman hanging around their husband.
"When you are widowed, you definitely find out who your true friends are."
After her husband's death, Elms used WAY's online forum and private Facebook group to engage with other widows and nurture new relationships. They would then meet up and go for meals or even on nights out and holidays together.
"I've met people who I wouldn't usually have befriended because we have different backgrounds and circumstances," says Elms. "You all have this horrendous shared experience and then you get to know one another and have a great time together, as friends.
"Even on nights out, if someone gets down, others will talk to them about it and say they understand - because they do - and that's really important."
Thankfully, with the wonders of social media, there are now many ways to stay connected with friends and family, which means nurturing relationships isn't as hard as it may seem. It's just a matter of getting into the habit of doing it.
Whether it's keeping in touch via emails, text messages, Whatsapp groups or, the fail-safe option, a phone call.
"Meet up with friends and family once a week and make it a regular fixture in your life so it doesn’t feel forced," says Neil Shah. "Schedule time in with your friends to do social activities like football or tennis.
"Or rope someone in to going boxing with you - there are many ways to bring in regular interaction."
Madeleine Mason highlights the importance of using social media to nurture not only our close friendships and relationships with family members, but to nurture our more "loose connections" too.
"These are great ways to create a sense of community around you," she says. "Engaging in posts by liking them, or even sending birthday greetings, are great tools for spreading the love."
So what exactly is the secret to a healthy relationship?
"The secret to any relationship is balance," says dating expert James Preece. "It's fine to be with a partner most of the time, but include your family and friends as much as possible."
Neil Shah, director of The Stress Management Society and author of 'The 10-Step Stress Solution', says a successful and loving relationship lies in wanting a person, but not needing them.
"Foster relationships where, every morning, you can kiss them and say goodbye - and that's it, you're in a position where you could let them go and live without them," he explains. "You should be in a position where you want them to come back, but you don’t need them to come back.
"A lot of people can get locked in the cycle of needing their partner to come back. This kind of reliance on a person leads to unhappiness, bitterness and breakdowns in relationships."
This February The Huffington Post UK is running Making Modern Love, a fortnight-long focus on what love means to Britons in the 21st Century. Built on the three themes of finding love, building love and losing love, HuffPost will feature human stories that explore exactly what it is to be in love in modern times.