When getting to the passage of Samuel 20:41 it had a line that said David and Jonathan kissed each other? I thought this a bit odd and was curious about it. 

In doing some research apparently there is a bit of a question as to if they were possibly homosexual lovers. This website has a giant write up about that topic disputing this theory: http://coldcasechristianity.com/2012/were-david-and-jonathan-homosexual-lovers

Another LGBT site that believes they were lovers lists their points here: http://qspirit.net/david-jonathan-same-sex-love/

My personal thoughts are that they were not lovers, but just very close.

Update: Hmmm… I found another site that makes some excellent points on why maybe they were possibly gay lovers. http://qspirit.net/david-jonathan-same-sex-love/