You mean EX-boyfriend, right?
Did you remember to poke holes in all of them just before you left (given that flimsy, very obvious excuse of his)?
I bet he claimed too that a "Dingo ate 'em all!"
Apparently, you weren't the only one visiting "Down Under" during those two months.... :-(
Better luck without him, OP! :-)

Don't jump to conclusions to quickly, obviously it looks bad but there's always a chance he was just being a good wingman

Yea, no. Then he oughta have admitted as such BEFORE reaching the bedroom....
Besides, who lets friends f*ck in their own bed? I sure as hell don't!
But you're right; it DOES look bad ... for a very good reason.

As a wingman, offer 1 or 2 condoms over 2 months? Sure.
But nine-10? "I don't think so, Tim." [Per US TV Show: "Home Improvement"]
Ex-BF is a dumb-*ss anyway for failing to re-fill the box to pre-trip levels, but I'm glad that he got caught. He certainly doesn't deserve OP.

Or he could be into water balloon fights?

That is kind of like when my mom said the condoms in her purse were my brothers. lol

On the bright side, he practiced safe sex on 11 of the times he cheated on you. A guy deserves a little credit for that, right?

Perhaps he just had a fancy wank.

11 of them?

You can’t tell me it seems odd that a guy has 11 wanks in a 60 day period? He probably had a lot more than that.

I've done this before so it's not too far off. it makes less of a mess

Condoms do make for easy cleanup after masturbation, especially if he's used to wearing them anyway.

Maybe your b/f has guy friends that used them?

And this is supposed to make things better?

I'm sure butt-fucking your male friends still counts as cheating!

Boyfriend has guy friend. Guy Friend wants to bang a girl. Guy Friend grabs a condom.

Didn't say anything about gay sex.

It was the third box

Go to him, hold up the box, and say, "Eleven reasons WE HAVE TO TALK..."