Being unsecure :(

I've been unsecure these last days.

The story starts here:
A girl S loves my bf very much even long time ago before i know him. Then he met me and they agree to be good friends. I know S, i talked, chatted and met her several times. She's sooo sad because of that, i know that. And my bf tried to cheer her up but i think she could not let her feeling go easily.

Most of the times i can off work about 6pm or more. Even today, i left my work at 8pm. He has an irregular schedule everyday due to his work. For her, she has tons of free time. So sometimes he and i had quick dinner and went home during weekdays, maybe 1-2 times a week. On weekend we spend time most together but sometimes he would go with her to watch movie on his laptop on Sunday.

He usually spend friday with her. And sometimes they also hang out few times in a week. Last month they spend a lot of time in Starbucks. He promised to heading home soon but then i know that they went home at 3AM in the morning :( I talked to him about this and he said that it will not happened again.

2 weeks ago my bf hurted ankle and could not walk but he already planned to watch another movie with her. So he invited her to spend Friday and Sunday for dvd movies (because Sat he and i had plan, then I spend Sat with him). I told him that i dont like the long time visit and he promised that he will not invite a girl to his house for more than a certain time. He offered to cancel his meeting/invitation but i said no, he should not cancel what he promised/planned to do.

Yesterday and today :
My bf planned a lot of activities with her this week. He told me yesterday that he will ask her to company him for some reason today. Then tonight he implisitely told me that he want to go with her to some place tomorrow and he told me another plan to spend Wednesday with her and another friend :O:O:O He has a day off on wednesday and i told him last week that I got a day off also since it is an election day of our govenor. But he did not invite me :(( He said that he forgot if i also had a day off either.
Wow ..

My problems :
I just think why do i feel so unsecure?
Am i normal to feel unsecure?
Or am i crazy to have too much thinking?
Why he'd like to spend a LOT of time with her?
Maybe he's bored of me :( Maybe he finds that she's better than me :(
I wish i could have more time with him. I wish i could available for him anytime. I wish i could ..

"For I know the plans I have for you," declares the LORD, "plans to prosper you and not to harm you, plans to give you hope and a future.."