Looking for some answers

Hi I've been dating my bf for about 2yrs now and who's 10 years older than I am. He's turning 50 soon and I love him to death. We met on a dating site and hit it off so well. The first several months were great! We're both divorced parents with kids. His are much older than my.child, but that's not the problem. We spent the holidays together and kids got along great together. My issues are this, valentine's day and anniversary he didn't even get me a card. Not that I'm looking for material things, but I believe that was somewhat disrespected and even lied to. For valentine's day he said he forgot my gift at his house and mind you I've been to the house a half a dozen times and still nothing. I just let it go, same thing for our 1yr anniversary. So now on our almost 2nd yr he constantly tells me he's busy doing work related things, but is always on social media. If I make a comment about it l, I'm being told that I'm accusing him of doing things that's he's not. If I express that I wish he gave me more attention I get the whole "you just don't get it". We argue more and more lately and it's because of his lack of ability to balance his personal life with his own business. If we make plans to do something I most of the time have to wait for him to finish what he's doing before we can go. Sometimes it maybe too late or I'm sitting there stewing with anger cause I constantly feel last on his list. Recently I finally told him I had it and didn't want to be together anymore. Well he cried and begged that I was the most important thing in his life and I'm what keeps him breathing and that he would change. And he did for a couple months but we're back to square one again. There's also a distance factor between us that I find myself driving back n forth all the time. Here's my dilema..... so how can I be his air to keep him alive when I feel like he let me die??