Getting so sexually frustrated&have an SO!!

I've been with him for 3 years. We use to have sex all the time. I've been living with him for about 5 months now. And we never has sex anymore. And it's not me who doesn't want it! I want to all the time, and he never does! We've only been having sex 1-4 times a month! I'm getting so irritable about it lately! I try to and he'll just ignore me, or say he's tired. And I've tried talking about it and he always says, we will tomorrow or somethin(then we usually don't) or he's just been tired. And I understand we have different work schedules and I get tired to, but there's still always time for it.... I'll text him stuff saying how I want to have sex and he just doesn't reply really. I just did today and he said nothing, and he's not home(he's getting his truck) but I'm so annoyed and mad right now. I just don't get why he never wants to anymore, it's driving me crazy lately. To where I'm getting extremely upset and balling my eyes out over it! (And no I know for sure he's not cheating on me or anything like that, so please no comments about that) anyone else having this problem?!