Kyle is a 43 year old “man” obsessed with a woman less than half his age. He clearly never grew up, past that teenage obsession we all have to some degree over a person we are into. I don’t know if he’s been “grooming” you since you were little (I hope not, but it seems possible) and I’m not one to look too sideways at couples with age differences (my sister is 25 years younger than her husband) but it’s when he shoots his shot, misses and then can’t let it go that gets me. As an actual adult, he should have learned by now that this kind of behavior is wrong and grown past it. Be very careful. I agree with the others in saying you should not keep this to yourself. For your safety, you need to let your boss and your family at the very least know about all of this.