I'm finally happy and then BAM

I found the man I will spend my life with. I'm pretty quiet in general and don't really tell the world my business.

My mom posted a picture on FB and hers isn't private.

For whatever reason, my ex was creeping. And about 2 months after she posted my engagement, my ex, and the father of my 6 year old (who BTW made it very clear he wanted nothing to do with him when I got pregnant - he has seen him 10 times his whole life by his own choice and doesn't support him in any way)

So my fiancé is his dad. Because he's the only dad he's ever known. Our son thinks he's just mommy's friend. Why? Not because I don't keep him from his dad. But because his dad doesn't want anything to do with him. Literally.

And I'm fine with it. His loss. I've been a single parent since I was 8 weeks pregnant. My fiance has been in our lives since my son was almost 2 years old.

Anyways. Enough rambling. Now my ex has reached out and wants to help and be involved and all of this (after he asked me if it was true that I was engaged)

He now wants to give me money and see him and buy him clothes and shoes.

I'm very apprehensive about what his true intentions are. Yes I know it is his child too. But he literally hasn't seen him in 3 years. He saw one picture when he turned 4.

My fiancé and I and our son have been living together for nearly a year now. Without sounding awful, my ex knows nothing besides the fact that I'm engaged. We've moved. And no I didn't tell him because he never talks to me. He's always changing his details. I don't chase him. He doesn't reach out.

What do I do here