The phrase "to be in" is an idiomatic expression that means to experience or undergo a particular emotion, state of mind, or physical sensation. Full definition
I once worked with a man who was in love with the concept of solar and LED. (entrepreneur.com)
Check all companies before you commit to buying them, merging with them or investing and you won't be in for any nasty surprises. (smallbusinessesdoitbetter.com)
Your blog is an inspiration to someone like me who is in love with food and following a plant based diet. (withfoodandlove.com)