hey there @Floofyboy welcome to the forums!!
sounds like a tricky situation to be in! i'm guessing being physically attracted to him is important for you to maintain this relationship? i'm curious - did something happen that may have contributed to you change in attraction to him? and do you feel like you're physically attracted to him when you meet on person, just not online? just some questions to reflect on, no pressure if you don't feel comfy responding.
from my personal experience, if i'm not attracted to someone physically, then i tend to find it hard to 'be present' and romantic with the person, and i feel like it would be unfair to them and myself if i pretend to like him. i've had friends lose physical attraction to the guy they were dating... and a lot of the times it worked in their favour because the guy wasn't actually compatible with them upon reflection.
i understand that he's a really dedicated and committed person, i wonder, is that enough for you to continue the relationship? or do you want more (i.e. physical attraction)?
(p.s. you can tag people using the '@' so they get notified of your response - e.g. @Floofyboy)