Your BF sounds like my husband. It is nothing for him to leave the house on Saturday morning. When I ask him where he is going he says he is exploring. He goes wherever his nose leads him and comes home some time after dark. He also may go off for several days. He can't tell me where his is going or what he is going to do because he doesn't know. I insisted on going with him when we first got together and found I was totally bored. I discovered that his time away was perfect time for me to pursue activities and interests that he does not enjoy. When we get back together we are both happy and enjoy our time together more.

I don't think he would change his plans for me if I asked him to or not. I've never asked. I do not own him. He does not own me. We are together because we want to be. As time has gone on we find we spend more time together. It works for us. Maybe it will work for you if you explore your interests as has been suggested.