[Marshall Placid]

It`s your call on this one OP.

I am assuming, based on your post, that they just started dating.

It`s your chance to show her how you feel by doing what the other guy has done: "officially asked her out".

You told her how you feel.

But, from your post, you did not officially ask her out.

That is my 2 cents: ask her out while her relationship with the other is still very, very new.

You also stated that she did not tell you that she and the other guy are going out.

So, technically, she thinks you don't know about the other guy dating her.

This is... an opening you can use.

Take a risk if she is worth it.

Or, regret it afterwards if you don't.

But, don't tarry.

Do it soon, or don't do it at all (ask her out).