Difficult even though I know it's the right thing, why?

My ex and I were considering getting back together a little over a month ago, we went on a few dates and it was really nice and felt good to be with and around him like that again. About three weeks ago though we decided that not enough had changed that the relationship could work but decided to go back to being friends.

This happend about 10 months after we broke up, I thought I was over him, obviously I wasn't. The thing that hadn't changed was the main reason we broke up... his female best friend. He had feelings for her while we were dating (denied it until the initial break-up) even though she was something we constantly would fight over. (He would go over to her house very late at night to watch tv series sometimes wouldn't leave till 2am once EVERY week).

He said he admitted his feelings to her about 3-4 months ago now but she wasn't interested and she said it's not something that will ever happen and because they are best friends they obviously didn't cut each other off after this and he still see's her every week for a couple of weeks and then has weeks/months before they will hang out again. In this aspect this has changed and it's not an all the time/planned thing and this I would have been okay with. However he apparently is still not completely over his feelings for her and this is why we haven't got back together. I don't particularly want to be second best anyway I mean he pretty much left me because of her and now that she isn't interested it was like he was coming back for me as second option which I didn't like.

I know I deserve better nor was I that invested yet, so why is it still difficult to keep moving on now? I still see him with mutual friends and we have been getting along okay- I'm abit uncomfortable at the moment just because only 3 weeks ago we admitted to still having feelings for each other and all of that happend, but we are still as friendly as ever. I'm trying to act happy and like this hasn't affected me in the slightest.
+1 y
After I heard him say that he confronted his feelings for her and that she rejected him, I kinda fell insult release and closure. I know his best friend we worked together we were friends also which is why it hurt a lot more and why I was holding onto it I guess. But now I know it won't EVER happen I feel like a weight has been lifted off my shoulders.
+1 y
I would also like to add that him going to her house he saw it as completely innocent and didn't think he was doing anything wrong. He knows he shouldn't have spent that much time with her or been there that late and while we were dating he was trying... he tried to not stay there as late but would go over the time sometimes. To me this wasn't a big enough change for me to notice though. He went over there twice without letting me know until after as well.
Difficult even though I know it's the right thing, why?
Add Opinion