Four months of no contact, and he calls me on my birthday

We broke up four months ago (he's from a culture that believes in family handpicking a spouse. I broke up with him the night he told me his family was getting ready to introduce him to a woman. He's never been married, he just turned 40, and the implied message was that the family says it's time for him to get married -- but to a woman that they chose). I didn't give him much of a chance to go into more detail. He said he hadn't met her yet, and that he didn't want to. I basically shut down, and told him that I can't see him anymore if he's going to be meeting other women, and to go meet her and live his life (I was in self-preservation mode and felt like I was being harshly rejected and I just shut down in the moment).

I never met his family, and the conversation about his culture / family came about when I started pressing him about meeting them. We dated for 7 months, long distance (actually, only about an hour's drive from each other -- still, long distance given our schedules). We saw eachother about 2-3 times a month. I'd never experienced the feelings that I had when I was with this man (and I'd been married before for 12 years). I fell in love with him and was heartbroken when I ended it with him.

After we broke up, he called me twice in a month's timeframe, and he sounded sad in his messages to me. The second message from him was wishing me a happy Mother's Day. I couldn't talk to him because I didn't want to get overly emotional...and I didn't see how anything could work out between us after finding out about his family / cultural issues. I called him back after his second call to me, a month after we broke up. We never spoke -- I just left him a nice message.

On our first date, I had told him about my birthday which had passed a few weeks before -- I never brought it up again after that first date. Now, four months have passed since our break up without us talking or texting or anything. Earlier this week was my bday, and he called and left me a sweet message wishing me a happy bday. He asked that I give him a call.

So, I am still very much in love with him and think about him every day. Of course I called him back a few days later, and we spoke about general topics. We were friendly with eachother, and he flirted with me. I ended the call after about 20 minutes and did not open up the pathway for future calls / dates, etc. I didn't bring up anything about our past relationship or any discussion regarding current ones. I kept it light and friendly.

SO!! My question: What brings him around now after no contact for months? Why would he have remembered my bday after me only telling him once -- on our first date, when he was driving?? It stuns me that he retained that information for almost an entire year (since my ex husband of 12 years NEVER remembered my bday...a bit of info I did not share w/ the ex beau).

Any advice or insight as to what's going on? I'm in the middle of the situation and cannot see clearly. My heart still hurts -- and I'm worried that I may not get over this...any feedback is appreciated!