To be carefree and in love

I'll sometimes see videos where a girl is looking at her boyfriend/husband in such a cute way and she's smiling and blushing. Or videos where he's making her laugh. And her laugh just sounds so pure and you can tell she's extremely happy.

I wonder what that is like. Being happy in a relationship where looking at him puts a smile on my face and makes me laugh. I imagine that it helps make life feel lighter.