I'm going to break up with my boyfriend because I find him unattractive
What is it about your boyfriend that you find unattractive?
It's not his looks that don't appeal to me but I no longer find him funny.
If you are not attracted to your partner in some way then a break up may be for the best. It's good that you are basing the decision on his personality and not his looks.
That's all I'm saying...
Ending your relationship with your boyfriend over personality differences is fine. It will help you to avoid wasting time in a connection that is not going to lead to anything serious.