That’s great you have a supportive probation officer and ppu (think yourself lucky, not all get that). I understand the relief of the sentencing feels like an ending (of one chapter at least) but as you’re already seeing, there's a new chapter to get through.
I guess from SS’s view, (remember they don’t know you personally, so they have to go through their very tough protocols which I'm sure you can understand), for example - you say you were happily married and had a good family life - but then your offence would have meant you would have sought to go behind your wife's back without thinking about the effects it would have on her. On top of that is how much younger the person you tried to communicate with being an upsetting shock to the mother of your child. Like you admit, it is a huge breach of trust and that’s what SS will immediately see.
The odds are stacked against you and I would assume that’s why SS are giving you a hard time, they are trained to do so, but they can’t end the relationship. It’s up to you to show your strength of character in how you respond, remorse for your family and show that reoffending is not “successful thus far with legal framework”, but simply inconceivable.
What I can say is that this will take time, I don’t think one conversation so soon after conviction will make SS go away anytime soon, so prepare for the long game and a lot of interference but if you stay strong the right outcome will prevail. Good luck!
Fighting or Accepting - its difficult to know which is right and when.