Simply put, the term “straight” is subjective at best. If that sounds like a complicated answer, that’s because it is. In fact, a straight man can fall in love with another man, period. The simple answer to what you have asked is yes, a straight man can fall in love with a gay man. You have a lot going on and so I’ll try to respond to your question as best as I can.
I can imagine sending this note was not easy and that it required a lot of courage to write all of this out in the first place.