As bb623623 said, I think you need to treat it as two things. I had similar experience as you, but not as complicated, as I do not have a child then.
Your ex-bf studied overseas, he seen things and experienced things without you being around, he may not love you as much before, why risk all these when you have already have a family of your own? For women, we cannot make any wrong move in our lives, as these kinds of things are never forgiven. If it doesn't work out between you and your ex-bf, you cannot return to your husband and child. And they will hate you forever. Carefully think about the consequences.
As we are sisters in bk kingdom, sincerely hope these advice will help you.
have you kept in touch with your ex-bf all these years? how old are you & your husband & ex-bf?
i don't know how men treat their ex-gf with kids. some will always have thorns in their heart even if he loves his wife. relationships with thorns and cracks are not perfect.
i think it's because you two (or should i say three?) are still very young. sometimes at such a young age, we do things out of 'feelings', but try to think for longer term, if your ex can accept you married and have a child, do you think he will accept this fact forever? will you change your mind if your husband correct his faults?
Excuse! Honestly, if your ex-bf haven't back to Hkg, do you want to divoice? If yes, it's fine. If no, I think you just treat yr husband as a "cow". "Riding a cow and looking for a horse". Don't be selfish. :evil: