Worried about what? You only said you've been seeing him and not that you're into any kind of a relationship. So he sounds to me like he's only a fu*k buddy, and since he only does it doggy style I'd say you're not any more than that to him even if you guys do have a good time when you're together. If you're wondering if he'll always stay with you I'd say no he won't, so if that worries you it should. I can't believe you give yourself to a guy so easily, not even knowing where you stand with him. I don't know if I have this wrong but if this is what you're looking for with him, just having fun and letting him bang you from the rear, then I'd say you have that and you will until he gets tired of you and finds some new fresh girl. I know this doesn't sound nice and I'm sorry for that. It's just that I wish that you'd understand the seriousness of having sex better than you do.
He's your friend, and you're his sex toy. His only wanting it doggy style means that he doesn't care if you get pleasure or not. If he really wanted to make sure you were happy with the intercourse, he would ask you what you thought, instead of dictating what you WILL do.
To reiterate, he's your friend. The fact that you hang out, and he texts you means that you're allowing yourself to be 'on call' for when he gets another urge. And the fact that he doesn't call you his "girl" is a no-brainer. Now you have to decide what you're going to do. Are you going to allow yourself to be used more, or are you going to regain some dignity.
It's hard to say just from that. Some guys just like it better that way. If you've been together a long time I'd be more worried that he doesn't call you his girl.
Scroll Down to Read Other Opinions
What's Your Opinion? Sign Up Now!uumm not about the doggystyle part because a lot of guys(myself included), are really turned on in that style. so don't worry about that, plus he texts you and hangs with you on weekends. so I wouldn't worry at all if I were you =)
The doggy style part doesn't mean he isn't into you.
Sexual Relationships 
Sexual Health 
Most Helpful Guys