Had a 3sum with an "ex-couple". Did they lie to me?

[enna]

I'm crushing on the girl (met her through a dating les/bi site).
I said yes to a 3sum with her and her ex boyfriend (who she claims are just best friends now) because I wanted to see her and he wouldn't not have the 3sum.

I had fun but there are things messing up my mind such as:
There was "Christmas card" in his room from her saying "to the one I love" on the front.
On his Facebook page it says "so lucky to have you (her name).

I just feel upset because I like her and thought something could happen but I also feel lied and betrayed even though I asked them if they are together...

[Steve]

You had a threeway.....enjoy it

Now move on