Relationship advice

About 18 months ago, my ex and I broke up. We were together for a whirlwind 3 months. Everything moved very fast. We were official, locked and loaded. He always showered me with lots of attention, made every attempt to call or text daily, if not a few times a day and I always reciprocated. He was very touchy feely and seemed to like PDA and I just wasn’t into that and he took that as me not being interested, when in fact, I was.About 2 weeks before we broke up, I told him that was planning a Valentines Day getaway for us to Santa Barbara. Hotel, dinner by the sea, all that good stuff. Suddenly, I found out that my brother was very ill and I had to take off up to Northern California for a few days that very weekend. When I told him about that he seemed a little miffed, however he said he understood. That entire time he was texting me and calling me and I couldn’t get to the phone because I was with family. On my last day there I was going to text him and let him know that I was on my way back and he basically broke up with me over A text message telling me that I was wrong for not texting him and wrong for not picking up my phone and that he never wanted to speak to me again. Obviously this was crushing because all I wanted to do was just spend some time with my brother who was in the hospital. So basically I called him selfish and we ended. We didn’t speak anymore.Fast forward 18 months, and my friend tells me that she’s planning a trip to Palm Springs for New Year’s eve. She tells me that she is inviting my ex because they are still really good friends. So I figure that I should text him and let him know that I’m going to this. We start talking again and basically I apologize for everything I did even though I don’t really feel like it was my fault. And he’s laying a major guilt trip. Now, I’m the one doing all the texting and he’s responding whenever he wants. Sometimes it’s within a couple of hours, Sometimes it’s over a day. I understand that my communication could have been better the first time around but I feel like at 35 years old this pettiness is really stupid. I miss him a lot but I don’t know if I’m willing to put up with this level of pettiness. Am I giving up too soon or is the writing on the wall?