To think friend can actually just piss off?

[xoxogossip]

Friendship group of 4, I asked (in person) if they wanted to go to a specific event and friend said “I should be free I’ll let you know”.

Now 3 weeks later she’s let us know she’s free. (She doesn’t have kids or work weekends for reference so it wasn’t a childcare issue).

For the last 2 years she’s been suggesting things and then when I ask she looks at me pitifully and states she’s far too busy to do that,

I’m tired of being a second option.

Shes just busy....

You value the friendship more than her. Mirror her interest.

Reply in 3 weeks

She's keeping her options open and waiting for a better offer. I wouldn't want to bother with her any more.

Well you either accept her terms or move on, and it sounds like you want to move on, so let her go.

Are you only allowed to be ‘busy’ if you have children or work weekends?

You can’t really let friends go if part of a group.

When is the event?

Some people operate differently. Have you talked to her about it?
I'm quite slow to reply to texts for a few reasons, but a friend recently said she needs to know definite plans months in advance or feels stressed so I try to make an effort to reply promptly to her, even though I don't like planning too many things in advance or replying when unsure as that causes me stress!

It would be useful to know when the event is. Has she given you all enough time to organise/plan it? If so then I don't think what she did was bad.
Not having children or working on the day of the event doesn't mean she doesn't need to check other plans. Maybe a family member was in the middle of setting a date for something, or she knew she had something already booked around the date you suggested, needed to check and then it went out of her mind because the event is a while away?
I think if you need to know by a certain time then you need to say "I'll be booking tickets on 1st Sept so can you let me know before then".

The second part (looking at you with pity) is pretty awful though.