How to introduce children to new partner

[Notmycircusnotmyotter]

I have a four year old and a three year old. I split with their father before my younger child was born. We are friendly co-parents; there is no drama and kids have only ever known us apart.

I've been seeing someone for two years. We were friends through work and it developed slowly and carefully into something truly brilliant. I trust him with my life, he is my best friend and biggest supporter, we are very very happy, we have never exchanged an unkind word, my friends love him. After a couple of years I'm ready to slowly introduce my children.

How do I do this in a healthy and non-damaging way? I would like us to live together eventually but the kids come first and we need to get this right.

I was in a similar situation.

The first meeting was very short and very casual - I’d made a cake for one of his colleague’s birthday, and he came over to pick it up. I told the kids that he was a good friend of mine and we’ve been hanging out a lot. He stayed for about 20 mins, chatted dinosaurs with my son etc.
After that, I very much took the children’s lead. For example I’d ask them “Would you guys be ok with DH coming to have dinner/come to the cinema/come to the park with us?” - ball was totally in their court.
They got along like a house on fire. Then it changed to the children asking me “Can we invite him over for dinner?” etc
We spent a fair bit of time all together and then one day I asked them “How would you guys feel if he was my boyfriend instead of just my friend?”….and they were happy about that.
Eventually the days spent together turned to sleepovers until we ended up living together full time and then got married. All of the above happened very slowly over the course of a few years.