Nothing in common?

I've been with my boyfriend for about a year and half now and slowly we are realizing we have nothing in common- apart from some musical taste and a little bit of our sense of humor. We get along well for the most apart- but the arguing and fighting has been pretty constant. He's very much into fitness, cars and computers whereas I am not much of fitness enthusiast, know very little about cars and computers. I try to show as much interest in the things he's into as I can ie: go to the gym with him when I can, try to understand more about cars etc..but I have been feeling like that gesture isn't reciprocated. I am very artistic and have a huge interest in writing, blogging and filming- but it turns out that he has interest in none of those things- nor does he really try to feign interest in any of those things. He participates in this online fitness forum where he talks to many girls (I feel like he flirts with them sometimes, although he denies that) and I feel like soon these girls will divert his interests from me because he can't talk to me the same way/ doesn't share the same hobbies as me. When I am not with him, he is talking in these forums and I am more or less ignored. When I am with him, it feels like our attention is focused heavily on being intimate rather than an emotional closeness. We are both very short on money so we don't have room to go on dates and such often- which does come into play and disconnects us from each other. I understand that it's not his fault; but I do long for someone who tries to be interest in me. I understand that the answer to my situation may be very obvious- I would like to point out I do like him because he's different than I am but its just hard to leave the realms of a predominantly physical relationship to an emotional one, which I would like to create more of. I have brought up these issues to him and have asked him to show me the things that he's interested in and to try to experience things that interest me-- but it doesn't just seem to click. He is either at a loss of things to say or he doesn't take me seriously. I am starting to feel like I am alone in the relationship rather than having that moral support. It is failing. This i have also expressed to him. What advice would you guys give me? Something I can perhaps try- or something I can talk to him about. I like the fact that we both have our separate lives and interest but I would also like to be included in a conversation sometimes. Am I asking too much, or should there be a limitation to how much couples share with one another? I thank everyone in advance for the support, please try to keep an open mind. I look forward to hearing from you all.

There's one rule in relationships and that's a happy couple will develop common interests if they don't share any. They have a need to be together and so they will show an interest in each others lives. It's all good that you attempt to show an interest and try to participate in your bf's hobbies...but, if he doesn't return it to you, then he really isn't returning anything to your relationship. Happy couples share everything..it's that simple. There is no limitation. When you have arguments and fighting then you have constant conflict and this is a relationship red flag and a warning sign that unless you guys can work through it, and it takes two, then you will eventually just part ways.

Thank you so much for your feedback. I truly appreciate it.