the FACT that you are NOT cheating on him .... is NOT important.
FIRSTLY ... IF your boy-friend was texting an ex-girlfriend or another girl who you did NOT know, would you be OK with that situation?
NEXT ... Only you KNOW the answer, that you WANT to be with your boy-friend or maybe you are bored and ready for a change.
BE HONEST with YOURSELF ... you are your number one FAN and you know how you truly feel ... and what YOU truly want. If you want to keep this boy-friend then stop this behaviour and focus on BOTH of you.
If you in truth WANT a change, fancy the HUNT, love the CHASE or anything, then there is NOTHING wrong with that either, since you owe NO ONE anything. As a young person, you are supposed to try out new experiences and different things, but remember to be HONEST with him, and take him out of his misery.
Lastly, be fair, and be HONEST with him, and be good to yourself.
Enjoy Life