When a guy sees a woman he deems attractive, his instant thought is that a girl this attractive must have a boyfriend.

This has to do with his assumptions.

In his mind, he can’t conceive that an attractive woman would be single.

This assumption takes the burden off of him in terms of the prospect of making an approach and risking rejection.

In thinking that the girl has a boyfriend, he doesn’t have to go through the rigor of approaching the girl and ruining his day when he gets shot down by her.

This is his mentality.

His get-out-of-jail free card.

Guys are terrified of rejection, and finding any seemingly justifiable excuse not to approach an attractive girl keeps them from being on the receiving end of said rejection.

A guy thinks a girl has a boyfriend when she has closed off body language.

She isn’t making eye contact with guys as she is going about her business.

She isn’t smiling at guys.

Her head is buried in her phone, as she rushes somewhere, not standing idle long enough to avail herself of her surroundings.

A guy who is attracted to a girl is looking for signs that she is open to being approached.

When she demonstrates closed off body language like this, he immediately assumes that she either has a boyfriend or she doesn’t want to be approached by guys.

That is why your body language is pivotal.

When you demonstrate closed off body language, you are giving guys a reason to assume that you have a boyfriend.

A guy thinks a girl has a boyfriend when she has a lot of guy friends.

Every time he sees her, she is with a guy or a group of guys.

When he sees her at the gym, she is working out with a guy or a few guys.

At the coffee shop, there are guys seated next to her at her table.

At the pub, she shows up with a number of guys each and every time he sees her walk in.

On her social media, she has a larger number of male followers than female.

Ditto for the gender of those who primarily like her posts.

These are principally guys.

He assumes she must have a boyfriend.

After all, a girl with this much male attention must have a boyfriend.

A guy thinks a girl has a boyfriend when she doesn’t respond in kind when he musters up the courage to flirt with her.

Flirting is a popular method that guys use to gauge whether a girl has any romantic interest in them.

He is hoping she wholeheartedly responds to the flirting by flirting back.

A girl who doesn’t flirt back gives him the impression that she is holding back so as not to disrespect her boyfriend.

The same applies to when he tries to break the physical space barrier by getting closer to her while in conversation with her.

A girl that backs off, keen on maintaining that physical space, gives him the impression that she isn’t alright with him being this close.

This must mean she has a boyfriend.