Many reasons... Most of the time its because he might be cheating on you.. (he mighttt) but maybe he is planning to celebrate something wonderful, and he doesn't want you to find out. Or also he could be in an activity that he might be embarrassed about for people to find out of. There are probably more reasons, but I can't name them right now... I hope this helped you a little bit.. :)
Be careful of second guessing your boyfriends feelings. He could be worried about many things or he could be depressed. This is where communicated comes in. Go for a walk or sit in a quiet place and have a talk with your boyfriend. Tell him you have noticed he is acting different and if he's not happy in the relationship. Don't accuse him of doing anything wrong. If he refuses to tell you then let him know that unless he can communicate on a higher level then how does he expect you to trust him. If he still doesn't respond then tell him perhaps it's best you separated for a bit to be sure the relationship you both have is right for the two of you. You be the mature one and by being independent you are in more control on many situations you will face in your lifetime. Take the risk because life is too short.
That can only be determined by talking to the person because each boy is different.
We say "acting suspicious" to describe someone's behavior or actions that seem questionable or cause concern. On the other hand, "looking suspicious" may refer to someone's appearance that suggests potential wrongdoing, but the more common phrase is "acting suspicious."
Well.....if he is acting suspicious or creepy that could be one sign. Another is probably is if he breaks away from you in an odd way. (WHO HAS THIS PROBLEM?!?!?!?)
He was acting that way to get the audience to like them.
If your neighbor is acting suspicious like something is up you should be worried!
Then be suspicious. He may have another girl friend.
(of a person or thing) Acting in a suspicious or conspicuous way.
tell him he is not your boyfriend and to back off.
If she is acting secretly and acting extra lovey dovey
if you start acting controlling
very suspicious i'd say . i'd take it into my own hands apparantly he doesn't want you to know who he's talkin to .
He can tell by the way you have been acting.
Harrison Gilbertson, my boyfriend