Very confusing man

I (32f) was hanging with a newly separated, not yet legally divorced man (39M). Him and his ex wife live separately and she hates his guts due to stuff in their relationship (I know, there are so many red flags to begin with). We were very casually hanging for a month or so, It ended when he forgot about tentative New year plans and I called him a jerk. We met up recently to discuss what happened, and he said he was falling in love with me when we were hanging out but that he can't be falling in love rn bc his life is completely fucked. I gave him a belated bday gift I had gotten him from when we were hanging. He said to me three times, with Everytime me saying "no you dont have to do that!", that he was going to get me a bday gift and think really hard and get something I love. My birthday came and went a few weeks ago, with no bday message or gift ....

Why would he say he would get me a gift and then not do it?!