Guy I liked now avoids me as he has feelings for me and already has a girlfriend

So I have fallen completely in love with a guy who I worked with for a few months. At first I thought he disliked me as he was always trying to avoid being alone with me and getting to know me but I would always catch him staring at me and he would try to be near me all the time even though he didn't speak much when he was near me . Well he left the company, and a few mutual friends have since told me that at the leaving party he admitted he had stayed away from me as he has a long term girlfriend and didn't want to cheat or be tempted as he was developing really strong feelings for me. He has mentioned this to two separate work colleagues on two separate occasions. They do not know each other and do not speak to each other yet what they say is exactly the same. He told one he liked me.

He used to get jealous when I spoke to other guys although he would try and hide it.

Now, I know his relationship has some issues, they have been together 6 years but never married or moved in together. So theres a possibility they will split up. If they were to split up, do you think there's any chance this guy would ask me on a date? We have each other on Facebook. For now he's trying to make his relationship work and I agree with that. I have no contacted him and never would while he is still in a relationship.

Or do you think that now we no longer work together or see each other his feelings will go?

I will of course date other people in the meantime. I didn't know he had a girlfriend until after he left the job and added me on Facebook.

only time will tell

If he was that unhappy he would have left his girlfriend, I would continue to leave him well alone.

I don't think he's unhappy exactly. But they are having problems and arguing a lot. If they weren't he wouldn't have developed strong feelings for someone else. He's a good guy and obviously wants to try and make things work for now. However, I can't see them staying together forever.