Both of you are attached and both of you know that very well,
your BF and that girl are only friends nothing more. The
possibility of your BF getting attached to that girl is very slim,
his friend wouldn't allow it, and your BF wouldn't risk the
friendship either so you can dismiss that thought.
You should blend in with his friends have fun with them, if you
keep quiet, you will only feel left out and there is when jealousy
comes in. If you're quiet while he's with his friends, he can't
keep quiet too can he? He asked you to go out with his friends is
because he wants you to communicate with them too, if he wanted to
spend quality time with you, then he'll go out with you 1-1
instead. The fact why you feel jealous when he's with his friends
is probably because you want your BF all for yourself, and thats
selfish, maybe thats why he feels annoyed and shows you that
attitude when you get jealous yadayada..
Or maybe you're feeling all these because you've spent too much
time with him. Sometimes even couples need to take some time away
from each other, to realize that they miss each other, they need
each other in their lives and without them, everything is different
and miserable.
When you're going out with him, you must well just enjoy every
minute with him by your side. If he's doing something right and
making you happy, smile at him and give him a peck on his cheek?
Showing him some appreciation once in awhile might actually guide
your relationship to the right path.
Well then, if you can't blend in with his friends or you're still
feeling jealous... its best to move on. Hanging on to a declining
relationship is very very miserable.
Well this is my first post so don't flame me or whatsoever =| i'm
just expressing my thoughts and hope it could be advice.