So these two guys.....?

I come down the corridor in work and these two men I work with are there.There used to be feelings between me and say 'Jack'.He never looks at me,not once.Instead he starts to tease the other man,trying to embar him.The other man walks off.Jack quickly leaves too.A few moments later,the other man returns and as he pes me,he touches my waist then goes to tickle me in a friendly..not creepy way.This other man is fond of me,but has never shown any romantic interest.Jack on the other hand,well there was a long friendship until we had a falling out months ago.Now he goes from saying hello to not looking at me in company at all.It's like he won't or can't.And this guy ain't shy.What is going on?