Boyfriend can never find time to text or call when he's out with friends or out of town. Am I more of a convenience to him than a girlfriend?

I just don’t know what to do anymore. My boyfriend and I have been dating for almost 3 years, and it’s like any time we’re apart he finds excuses as to why he couldn’t text or call me all day. If he’s out with people and I have any sort of emergency and try to contact him, he just won’t answer my texts or my calls because when he’s out he likes to “give people his full attention and not be rude.” and he doesn’t even have his voicemail set up. Which I get, to a certain extent, but if he calls me, or texts me, unless I’m physically unable to reach my phone, I will answer and I’ll be wherever asap. I don’t make excuses or put off answering. He’s even gotten mad at me for coming home on break during his day off because he didn’t know I’d be there? When in reality I thought he’d be excited because we barely get to spend time together due to our schedules. But if I don’t get back to him immediately while I’m at work he gets suspicious of me and interrogates me, he’s even accused me of going to work early or staying late to spend time with a coworker(who has a girlfriend) who he thinks I find attractive.. when I’m actually just doing work. I don’t get it. I personally feel like more of a convenience than a girlfriend. If there’s ever going to be conflict about something he just lies instead of facing it. I just don’t know if I’m overreacting or being too hard on him or if how I feel is justified. He tells me he wants to be better, he acts super nice, and then immediately after doesn’t put much effort into talking to me or communicating with me outside of a few texts, especially when he’s out of town. I understand being busy, but I want him to find excuses to call me and not the other way around. No clue how to approach this anymore, any advice would be great.