My Sagittarius boyfriend never replies to my text messages and never takes the initiative to look for me.

Your boyfriend is completely in control. He treats you when he wants to, and ignores you when he doesn't. He is not enthusiastic about you, "he never replies to my text messages

and never takes the initiative to find me", but he is reluctant to give up on you completely, "Ignore him"

He will do it himself "Run out to me", he doesn't love you enough, but he doesn't want to lose you.

I think your relationship is very dangerous. He "missed" and you can't seem to find him at all, unless he shows up on his own. In fact, you are not as familiar with each other as you thought?

And he is always busy, so busy that when you need him, you can't find him when you want to look for him. You are very unhappy. Maybe he is not suitable for you.