A colleague

I’m here looking for outsiders advice, the age-old question ‘what do I do?!’

So here’s the situation:
Early last year (Jan 2019) I started a new job in finance. We’re both consultants. One particular person (in question) and I immediately hit it off as friends. We worked together quite closely being on the same team, and so we spent lots of time together, saw clients together, reflect together etc. We goofed around a lot, it was great fun working with him. Fast forward about 8 months, I had this sudden realisation that he might have feelings for him. I always thought highly of him as a friend, and acknowledged the potential for more, but never considered him as anything else as he has a girlfriend of about 5 years (with a few breaks in their relationship). I reflected on much of the time we spent together over the past 8months, and noticed that these hints slowly crept up on me without my knowing. I decided to be an ‘observer’ to this idea that he could think of me in more than a friendly way. In a very short time, it was obvious that this was more than just a suspicion, and our colleagues started making little comments (our team is very well bonded) about our interactions. A close colleague questioned him kindly about his relationship with his girlfriend. He had alluded to me several times over the time that I had known him that things were difficult between he and his girlfriend, but he seemed to be working hard to fix things. He admitted this in greater definition during our Christmas party when we had a few drinks. He remained inhibited out of respect for his girlfriend, but it was clear to me that he had been really struggling with her for a long time. He feels ready for marriage and kids, but she’s not sure she wants either of those. He is quite a passive, caring guy, so I believe he is struggling to end things with a girl that he has been with since they were a teen. He also opened up about his fears of being in my situation (single) and having to date. The conversation certainly highlighted many of his fears. He ended up inviting me around for movies and drinks after the Xmas party. I didn’t stay long, we sat around with his housemates chatting while his girlfriend was asleep. I decided to leave shortly after fearing what may be if I stayed longer…I didn’t want things to go further than would be right for both of us. Nothing inappropriate happened.

Shortly after, I ended up moving departments. I still see him often, I thought my feelings would go away, they haven’t. He’s still trying to fix his relationship, I’ve not gotten involved with this too much. It’s clear there’s feelings between us, and I definitely don’t want to be the ‘other girl’ but I don’t know what to do. There’s clearly problems in his relationship, but he also fears leaving. We’re clearly very connected, and I won’t let anything ‘happen’ between us until he has split from her. I have continued to see other people, but I’m struggling to connect because of the feelings I have for him.

I don’t know what to do. The simple answer would to be to back right away, I understand, but I wonder what my other options are. What are your thoughts?