A: Not trying to be rude, but honestly, if I were him I would think you're pathetic. You wait that long to say you're sorry, and you obvi had huge issues before. I'd ignore it completely and I certainly wouldn't reply to you. Harsh? Yes. But it's too little too late.
A: In my experience, the first sign is spending less time with you. They begin spending a lot more time with friends, instead of with you. What I did was just give him some time, he came back around when I became less available too.