He isn’t sure about whether he has found what he is looking for.
Saying that you are his girlfriend would feel too final and he doesn’t believe that dating you for 6 weeks has been a enough time to declare you to be his girlfriend.
Calling you his girl feels a lot safer as it doesn’t feel quite as official.
He is enjoying your company but he may be really hesitant about committing.
If he has already told you that he started online dating in order to find a serious relationship, there may be something that he is not getting from you that he believes he needs.
If you recall some of the conversations that he has had with you, you may be able to get some clues as to what this may be.
During your conversations with him, he may sometimes talk about a certain personality trait that he tends to like in a romantic partner.
Perhaps this was a personality trait that one or more of his exes had.
If you notice that he mentions this personality trait quite often, there is a good chance that this may be what is missing in his relationship with you.
Hence, this may be why the both of you have been dating for six weeks but he won’t say that you are his girlfriend.
There may be a part of him that is waiting this out in order to see whether you will show him that personality trait.
Perhaps you have had discussions with him in the past and you have mentioned that you have this particular personality trait.
However, he may have yet to see that personality trait in you.
This may be what he has been waiting for.
He may be holding out hope that you will eventually show him this personality trait that he so longs for.
This may be why he calls you his girl.
He may be hoping that by calling you his girl, you will get comfortable enough to finally bring this personality trait out of you.
Hence, he waits.
It has been six weeks and he is yet to see this personality trait in you.
Being that this personality trait is often what he needs to be present in anyone that he would officially call his girlfriend, he has yet to tell you that you are his official girlfriend.
Being that you met this guy on an online dating site, there is a good chance that he knows that you may be getting attention from other men.
Women tend to get a lot more messages from men on online dating sites than men get from women.
By calling you his girl, he may be hoping that you don’t feel tempted to get on the online dating site and talk to as many men as will send you messages.
He may be hoping that you are hooked on him at this point and thereby you are able to focus all of your energy on him.
If he is to ultimately discover whether you can give him that missing element, he wants you to be fully focused on making him your boyfriend.
Indeed, he already knows that this is most likely what you want.
As long as you are fully focused on trying to make him your boyfriend, he wouldn’t have to worry about you becoming distracted by other men who may be sending you messages on the online dating site.
Hence, by calling you his girl, he is hoping that you have developed a sense of ownership over him and thereby will do all that you can to provide that missing element that he so desperately needs in a long-term partner.
Until you get him there, he will keep his dating options open by maintaining an active online dating profile.