Threads on MN tend to rattle around in my head, I was thinking about his behaviour, and I honestly think there's a chance his "love" for her and apparent burning desire to get back together....was actually the excuse & motivation he gave himself to run away from a pregnancy/child.
I think he possibly latched onto that to give himself his justification/rationalisation for feeling the UK and returning to Colombia, which facilitated him having zero contact and responsibility for his child.
I think the prospect of a child can be terrifying, even to those who planned it , when it actually happens.
And that's for a non sociopath/narc - which he appears to be.
In spite of all the BS about wanting kids - I think the reality is that he was shit scared, didn't want the responsibility (and especially didn't want it in alien, rainy Britain with a woman who didn't share his chauvanist cultural values). I reckon he utterly shat himself, thought "I'm not doing this", and legged it. I think he did it before your baby was even born so he wouldn't feel any even worse/shittier about what he was doing.
He said he'd be there for you, but he left you before the baby was even born, hasn't seen them once in person, hasn't paid a penny to support them, and didn't make any effort to amend his travel plans to see his child in Mexico when his child was brought to where he'd be passing through.
He wants to believe he legged it because he needed to reunite with the love of his life, and he's telling her that, and others that ...that's the narrative,; but what people tell themselves and others about their reasons for doing things is often lies. They need a lie because they can't say to themselves, let alone others, "I don't want a child. I don't want to be a parent, I created them but I don't want that. I ran away".
You see it lots among men who use all sorts of excuses as to why they don't see kids they fathered .. the favourite one being "she wouldn't let me see them" or "she poisoned them against me" etc. But it's just excuses and lies. They don't want to be bothered. They don't want the responsibility. They don't want the "work". They don't care. They know people will disapprove so all sorts of excuses and lies and manipulations have to made.
That's why he's cavalier and disrespectful and offhand in the video calls too, possibly. He doesn't even want to be doing that ... But he probably feels like he has to in order to appear to be keeping on contact with his child. It salves his conscience, he can tell himself and others he hasn't totally abandoned his child.
(He might also have an idea that keeping contact will enable to claim a relationship for future visa applications if the US doesn't work out).
I have my doubts this great love he has for her (symbolised by a cheap tat engagement ring he's lied about, and classy matching tats) is really the main reason he fled the UK. More like an excuse to dump his gf and child, pand run. And now she's rather useful for his latest immigration attempt too.