tell me the difference please...

[chum]

what's the difference?

1. I'm really glad that I met him...

2. I'm really glad to have met hima..

3. I'm really glad having met him...

the situation is...I've met a new friend at work and we have the same interests when it comes to sports...and now we enjoy each other's company...

[MrPedantic]

Hello Chum

1. I'm really glad that I met him...

2. I'm really glad to have met him...

It seems to me that both versions would suit your situation. It's difficult to say which would be more common; #2 feels slightly more likely to me, but it may well vary from region to region.

#3 isn't correct, in your context; though it's possible to find a home for it:

3. I'm really glad, having met him, to find that he isn't as strange as his emails suggest.

But it's a very unusual formation, and so best avoided.

MrP