In any relationship, setting boundaries can be incredibly important to ensure both parties avoid any unnecessary hurt or upset. As it's when these lines get crossed that problems tend to arise.
One man has found this out the hard way after failing to set boundaries with his wife around her best friend.
Taking to Reddit, the unnamed husband claimed his wife is a stay-at-home mum and her male best friend is always at his house while he is at work and is still there when he gets home.
The man has become such a strong presence in his home that he says his son even recently called the other man 'dada' which has made him feel rather uncomfortable about the relationship between the two.
Writing on Reddit's relationship advice forum, the man asked fellow users if he should say something to his wife about the situation - and many were quick to offer him a warning.
He wrote: "My (32m) wife (25f) is very close with her guy best friend (27m) and I'm not sure if I should say something?
"She is seeing him a lot more than she sees me now and he's often over at our house and my son even called him 'dada' which rubbed. me the wrong way."
To make matters worse, he says his wife merely "laughed" when the child said this and did nothing to stick up for him.
The parent goes on to say that he doesn't want to seem like a "controlling guy" who wants to "cut his wife off from her friends" but the whole thing has left him confused.
"I feel like he's spending more time with my son than I do as he's always over and I work long hours. He works night shifts so during the day he's almost always at my house and I come home to him being there. He's constantly there doing something with my son and my son loves him which hurts me as I want my own bond with him and I feel like that's been taken away from me," he admits.
The man goes on to say that he's expecting a second child with his wife and is now considering cutting his hours at work so he can spend more time with the family - but she wasn't so keen on the idea.
He added: "I just want my kids to bond with me and not that man. She doesn't seem to understand that parenting is a team and it's almost like she doesn't want to be involved. This has just made me realise that I need to be more involved than her guy best friend is and I don't know how to peacefully go about that. Any advice?"
Hundreds of people responded to the post, with many encouraging the man to have an honest conversation with his wife, while others urged him to get a DNA test to confirm he is actually the father of the children.
One person said: "It's time to have an honest discussion with your wife about this situation. Explain that she's spending too much time together with him. Being a SAHM doesn't mean him hanging around constantly."
Someone else replied: "DNA test immediately."
A third commented: "Cut your work hours. Tell your wife you will be spending more time at home. You don’t have to ask permission to spend time with your family. And tell her her friend needs to cut the hours he spends in your house. Her response will be telling."
While a different user added: "A paternity test may be in order - both for your son and the one you are expecting. I get that people are allowed to have friends of the opposite sex, but this situation is extending way beyond that and you are actively being supplanted by her friend in your own life."
What do you think? Let us know in the comments below.
