I meet FLIP

This is the ongoing story of one of the men in my life.  Flip (not his real name) and I have become very close friends.  He is partnered, but his partner doesn't seem to fully understand his needs and therefore does not meet them all.  They have been together for a fairly long time...to me that means at least 10 years.  I suspect that their relationship was suffering from the same doldrums that many relationships suffer from, after that length of time.  Both partners need to work at the relationship to keep it fresh and meaningful.  I have become 'the other guy' in his life, and I am not real happy about it.  This is how it started.
Flip sent me an email through silverdaddies...his profile was nice.  A few years younger than me, HWP, a vers/bottom who loves a passionate top.  I agreed to meet for lunch which led to a hotel room nearby, and a very enjoyable couple of hours of hugging, kissing, and sucking.  When he left, I felt like he could be a regular, I enjoyed what he did for me.  Starved for affection, I felt really good that someone wanted me.  
We met the following week at another hotel, and had a great time.  We seemed to fit together well.  I am strictly a top, and he loves to bottom.  He is always horny, and has a good size, larger than 'average' cock that I enjoy playing with.
Within a month, I found myself on a business trip with him...just a three day trip...I met him at the airport in Cleveland after he dropped off his partner to return home.  For the first time in my life, I checked into a hotel room with one king sized bed with another man.  As paranoid as I am, it was a huge deal for me to be there, knowing that 'everyone' knew were are gay.  He spent most of the day working, but when we went to dinner, I felt like everyone knew we were a couple.  Although there were no outward/obvious displays like holding hands or kissing in public, we would play footsie under the table, and spend most of our time looking at the other guys, talking about who else was gay or who wasn't but we wish they were.  
The sex was great.  To lay in bed with another man, sleep with him, and wake up with him was everything I expected and more.  It felt so good and almost 'normal' to me.  I was afraid I was falling in love.