Does it make me deceitful if I am starting to fall out of love with someone but not telling them right away?
Probably, what is making you not tell them you don't love them?
I really don't know, I just can't love them anymore.
Sometimes people do grow apart and that is okay but you should be honest to your partner so both of you can move on and be happy with other people.
It's not like I don't want to tell them.
It's respectful and the right thing to do to be open and honest in a relationship, plus it makes you look mature rather than petty.