Why would he invite my friend?

Previously before we had a fight, he never invite my friend to eat. He is not that close with my friend, they can never be just 2 of them together.

Now, everytime when both of us want to eat (he invite first) then suddenly he will ask my friend if she want to join too, but she has a boyfriend.

So i dont know why is that? Is it out of courtesy because we are walking together 3 of us, or is it because he no longer want to go out just the 2 of us?

(We are not couple, but a complicated situation)

Why would he invite my friend?
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