Everything happens for a reason???

A month ago today my best friend (Josh) experienced a horrible tragedy- his girlfriend of almost 2 years was killed suddenly in an auto accident. Leaving him to raise their 2 year old son (her son in which he is in the legal process of adopting). I went to the viewing and as much as I hate to say it- there it all began.
Going back to the beginning- I’m pretty sure I fell in love with Josh when we were about 10 years old. He and I were best friends and inseparable. Fast forward to high school days- he was the guy that got “stuck in the friend zone”. Any time I needed him- he would be there. We had the relationship that people often mistaken us for “dating”. But as much as he wanted to relationship- I had bigger plans. He wanted to stay in our hometown and work for his families saw mill business and I was headed to the “city” to be a big time designer. Going forward a few more years- in our early twenties I realized that he was most likely “the one”. I can’t say we ever really tried dating but it seemed over the years we would contact each other when something in our life wasn’t going well. He was always the guy I could call in the middle of the night to pick me up for a drive so we could talk. He was even the guy that I expressed my fears of marring the wrong man before I married my ex-husband. Those late night talks would usually lead to us discussing why we never worked or how we both had feelings for each other but it was never the right time. We always had outstanding relationships. This was NEVER a hook up thing, in fact, other than the occasional shared kiss, we never did ANYTHING else. After our initial meetings for whatever the reason is would start this whirlwind. We would see each other and talk almost every day but within a few weeks, we would just let it stop and we would drift apart. I would say we have had these escapades about 5 times in 8 years (we are now almost 30)- always coming back to our comfort level with each other and picking right back up where we left off- like we never missed a day together.
About 2 and half years ago- I was going thru a separation with my then husband. Josh and I met randomly one night at a local gym and once again our whirlwind “relationship” began. We even talked about how we might actually have this figured out this time. This time last a lot longer and was by far more serious than the other times and we ended up sleeping together. But without explanation it ended. A few months passed and as I was about to reach out to him and ask what went wrong, I heard he was dating someone new and she had a child and Josh had really “taken” to her son. I did what I thought was best for Josh and stayed away. Seemed like he had what he wanted and I didn’t want to do anything to mess that up or bring back up the confusing and unanswered questions of what if.
Then a month ago tragedy struck and Brandy was killed. I went the viewing and from across the room he saw me standing in line. He froze and our eyes met and I just started to cry. We stared at each other across the room for some time. We spoke briefly that night and I had sent him a few texts in the days that followed seeing how he was doing. Over the last few weeks we have seen each other every few days and for the most part we are once again picking up where we left off. We talk about Brandy and the things he fears being a single dad and we talk about how ironic life is and how even though we NEVER thought we would have this chance again- we do. I am grateful to have this opportunity again- I am finally divorced and oddly enough it seems like we are both at a point where down the road we could start something. But I can’t help but be sad for the reason this opportunity is even here. And my bigger concern is how to deal with both emotions. We were talking on the couch one night about 2 weeks ago and he kissed me and sometimes we curl up on the couch together and watch a movie. We have a great comfort in each other and that comfort is familiar because of our longstanding friendship. He has told me he is able to separate his feelings for me and brandy and while he was very much so in love with her- his feelings for me had never gone away. But some days are good and some are bad. Today was not a good day- he was very depressed (which is understandable) and told me he was never going to be over her and anyone he dated would just be sub-par to her. I just need some advice from anyone that is a widower or has dated or married one. I want to be his friend and be there for him but we have feelings for each other and keeping the 2 separate is a VERY fine line.