Cheating with the same guy

I am in a need of an advice. In a relationship for over a year now and couldn't be happier. I love my partner and can't imagine to spend my life without him. As cruel as it seems I have cheated on him and not once😓 with this guy I met far earlier than my bf who became a very good friend of mine. We used the have the "fling"& the "thing" and all that as it apperars we still do. He is in a relationship as well for about the same time as I am. We live in different countries so we only see each other every month for few days when I am there for work. I could go and visit more if I wanted to but I am not sure it's doing anything good for us?!!! It's always the same, I am so happy to see him I know I will have stress less time and attention and we will do stuff together we don't do usually and go to places we would never go with other people and he will not feel lonely away from his family that far as he is. Also lots of emotions, endless talking about everything and amazing sex than reality hits..... I feel awful I love my bf and we are planning to get married. The other one is begging me not to get married or take any decisions even thought he is in a relationship too. I don't get him. He is not opening up only few times so as much as I try to read him I can't. The last time I had seen him he messed me up completely. Usual thing happened our moonlit night on the beach drinking rum which became our routine every time we meet the first night (just to clarify we never ever get drunk together) just talking about life and enjoying the night.... But that night became far more romantic than any other before..well apart from the very first time we met and we're both single. Anyway cut the long story short it felt amazing and again we ended up making love on the beach but this time even thou we both are in a committed relationship he wasn't careful. In fact he was well going for it and I didn't stop him. This might sound stupid but I couldn't and I don't know why I just couldn't. We talked about our relationships I know she isn't the one for him but he knows I love my bf dearly which doesn't make sense at all trust me guys. I have never been more confused in my life than now. I've always sensed that somehow he wants me to take the decision to ask him to leave the girl and be with me but he knows better that I would never do that! It has to be his own decision without me interfering in any way and obviously he has to come to terms with the fact that he might end up alone as I will have a choice to make. It will be hard for me I love my partner but I don't actually know what would go through my mind if he was actually single now and after all this. After the last time I sent my "lover" a message saying I can't do this anymore and how everything is complicated and I wish someone would give me an answer. All he replied was "safe flight my love the countdown until your return begins once again"! I also can't find an answer for why we never tried together when we were both single? I feel bad and horrible but is it possible to be in love with them both??? Is this normal? They are both amazing and in both of them I find things which will make them be the person I can't live without. Selfish I know.... Anyway all the opinions and even judgements are welcome as I am very lost right now and could use some advise regardless if it's good or something I am not willing to hear. I can't be any lower than this and I don't want to loose any of them so what do I do now??? Thank you for being able to vent....