this is a very similar scenario to what I have experienced. Maybe I could share it with you, to comfort you that you’re not the first to go through this.
I was with my ex-partner for 4.5 years and, about 1 year into the relationship, I began to develop a nagging gut feeling that it just wasn’t right. I did managed to bring it up a couple of times (after stewing iver it for weeks or mobths each time!) but each time he queried what the problem was, like I needed to give him a soecific reason. The fact was, though, that I had no other reason but a gut feeling telling me it wasn’t right. So each time we said we’ll give it another month and then talk, but we never ended up talking and it was always on me to initiate the discussion the next time. Long story short, I sat on the fence and he was happy in just a mediocre relationship for too long. I even said yes to his marriage proposal because I didn’t think I could say no.
In the end the distance between us grew so large, but I could ‘t physically utter the words, “I want to break up”. No matter how prepared I felt, the words stubbornly would not cone out. So I hand wrote a letter telling him how much I loved him but that we needed to seriously think about whether our oartnership was viable. Writing instead of a confronting discussion gave me the chance to fully express myself without challenge. He agreed with me and suggested we end things.
If you’re scared of regretting making the wrong decision, and you feel open to working things out with him, maybe you could tell him a bit about how you feel and ask for his opinion as to how you could both improve things.
One thing to remember, if you’re worried about ruining someone’s happiness, is that, while you should be kind and courteous, you are ultimately not responsible for someone’s happiness. It is not your job to keep someone happy at the expense of your own.
wishing you all the very best.