Significant other

Idiom: significant other; used as a noun.

First Example:

Christina: Bryan, I just got a wedding invitation from my friend, Ryan. Would you like to go with me?

Bryan: Sure, but can you bring a guest?

Christina: Hmm. Well, it says the only guests allowed are children and significant others.

Bryan: Then I don't think I should go. Roommates don't count as "significant others."

Meaning: "Significant other" is used as a vague term for another person's partner in a romantic relationship. It is often used formally in things like invitations, when it's possible the person could have a husband/wife or boyfriend/girlfriend. In the above example, Bryan says he can't go because "significant other" means more than a friend or roommate. However, "significant other" can also be used informally, either because a person wants to keep his/her private life secret, or in a question to find out a person's relationship status and/or sexual orientation.

Second Example:

Laurie's Boss: Who was that on the phone?

Laurie: My significant other - I need to pick up some eggs on the way home.

Here, Laurie is avoiding telling her boss what her relationship is exactly to the person who called her, so she just said it was her "significant other."

Third Example:

Laurie's Boss: Why do you always use "significant other?" Why don't you just say "boyfriend" or "husband"?

Laurie: Because "Susan" is actually my girlfriend, but I didn't want my sexuality to make you uncomfortable.

Laurie's Boss: Oh, of course it doesn't make me uncomfortable! Actually I should have guessed.My little brother used to use "significant other" all the time for his boyfriend, Christopher.

Here, Laurie used "significant other" to hide the fact that she is a lesbian.

This idiom is from LSI's book "Reading Horizons," which is used in the Level 6 Reading classes. 

https://languagesystems.edu/

Those three little words

First Example:

Rachel: How was your weekend?

Charlene: Fantastic! Tom took me to a really amazing restaurant, and then we went for a walk on the beach.

Rachel: Aww! That sounds so sweet!

Charlene: And then the best part - he finally said those three little words I've been waiting for.

Rachel: Wow! So you guys are really getting serious! 

Charlene: I think so.

Meaning: The expression "those three little words" refers to the phrase "I love you."  Since "I love you" is considered such a strong and powerful thing to say, we often use the phrase "those three little words" to refer to the phrase in conversation.  Usually, this is used when at least one person in a couple hasn't said it to the other, but it can also be used for the first time one partner says "I love you" to the other, as in the above example.  In this example, Charlene is excited because Tom finally told her that he loved her.  

Here is another example:

Dale: How are things going in your new relationship?

Colby: Pretty well.  I can't believe we met online.

Dale: How long have you guys been going out?

Colby: A little over a month.

Dale: Wow! If you don't watch out, someone's gonna slip up and say those three little words!

Colby: It wouldn't surprise me. I'm actually really happy

Dale: Glad to hear it.  You two seem like a really great match.

In this instance, Colby says that his new relationship is going really well, and Dale jokingly warns that someone is going to slip up (which means "make a mistake") and say "I love you" to the other.  This expression is often used in contexts such as this, when a relationship is getting serious but no one has said "I love you" to the other person yet.

https://languagesystems.edu/