Married male co-worker keeps buying me stuff. What do you think his intentions are?

I’ll try to make a long story short. I’ve been working with this guys for a year. I work under him technically. My work best friend, Him, I have all gotten pretty close from working so closely together. Anyways, it all started with him asked if I’d come in on one of my days off for extra cash out of his pocket to complete a job with him. I agreed thinking nothing of it as more then a business transaction. I was the only one he offered the opportunity to. Next, my coworker and I decided to both chip in and get him a small Christmas gift together. Nothing crazy, just a small gift. A couple month later he gifted both of us expensive shoes. I also took this as just a friendly gesture since we had given him a gift as well. However, last week for my birthday I receive another gift from him that was very expensive. From my knowledge he has only given me a birthday gift nobody else. Not even my work friend who just had her birthday last month. I’m not sure how to take this. He is married and been with his wife for a long time. Do you think these gift might have an underlying meaning. Or am I just overthinking it?

Married male co-worker keeps buying me stuff. What do you think his intentions are?
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