Sharing Our Innermost Thoughts

So I am going through a lot these days I know all my problems will be stopped if I stop overthinking and just be and live the moment but no matter how hard I try I’m overthinking about it… so I have a relationship of 6 years now, he is a very awesome person he is a great partner in every way he was perfect for me with all his flaws and all his imperfections. But 2 months back I came around a boy and I instantly had a crush on him I tried to stop myself a lot but I fall in love with him (one sided) and than somehow we started talking and I got to know that he is same as me and in just 2 months we have became very close and we shared our heart out we still can see and believe that we are exactly same and he understands and gets me very well in just 2 months which is actually not possible. And now he knows about my boyfriend and he supports me that I should be with my boyfriend because my boyfriend needs me more than anyone as his mom passed away 4 months ago. It is still shocking for him and he is not able to get over it and he needs me the most and I’m there for him always as he is my best friend also we have a special bond and I know I’ll be happy with him but now the thing is that I don’t feek the same for him anymore that used to… I overthink that I’ve done wrong he doesn’t deserve me anymore but I can’t leave him like this because he doesn’t have anyone else now