When your guy starts ignoring you this is a warning flag. Something isn't right. If a guy is smitten with you, he is not going to ignore you. Quite the opposite, he wants to make you happy. If your guy is ignoring you he could be pulling away from you.
First of all, one reason he is ignoring you could be a simple case of he is taking you for granted. Why though? You probably think you are being a good girlfriend. You would do anything for him. We women nurture by nature. Ask yourself are you acting more like his Mother or his lover. If you nurture him too much he may be feeling more like your child than your boyfriend. You need to trust him to take care of himself.
Men fear at a core level losing their freedom. If you are clingy, insecure or needy, he may view you as a threat to his freedom. A man needs his space and if he feels he can't get that without upsetting you, he feels he can't live his life and make you happy at the same time. When a man feels he is no longer making you happy or that it's too much sacrifice of himself to do so, they start checking out.
When a guy ignores you, he is usually trying to keep you at arms length. He feels that you are more invested than he is. He doesn't want to talk about it because he fears your emotional reaction or you creating drama, so he just goes into ignore you mode.
One thing is certain, when a man begins to ignore you all of a sudden, a pull away in in your future. The instinct of most women is to hold on tighter, but that just causes him to pull away more. Don't make this mistake. Find out what to do when men pull away before you blow it for good.