@ibelieveinmirrorballs
That's absolutely mental with your colleague! 
Agree it's so common for people to say "we must meet up/do X" and then it never happens, not just dating, so never should be taken literally. Until someone is sitting opposite me I don't believe anything.
I do think it does work both ways as well, I've found at times in dating I've maybe had to retreat for some private reason, the best etiquette/policy is just to not overinvest?
Especially at the first-second meet stage, there's a lot of "one-date wonders" out there!
Like with my iron from the spring/summer MrPM (that long ago now I can't remember
) we had a nice first meet (dinner), second meet strongly proposed from him, I responded positively, didn't happen
.
So I just got on with my life, dated others, as sending a "closing" text seemed a bit intense/excessive.
I actually don't mind exchanging a few random WhatsApps with him now (he sent some messages on Xmas Day as he works on ships), it's a bit of an ego boost (I don't mean sexting just polite compliments) and I've not put my life on hold for him?
I'm in a new city/workplace and I've joked with other new starters about how we've all had great social meets with people we never see again! But it's just busyness it's not personal.