There's a difference googling for e.g. professional qualifications, speciality et al. and purposefully seeking private and dare I say, sensitive, information such as tax records, info about mortgage, interior of house, family etc. I find that really iffy. We don’t always have a say in the information that is available about us and it could easily (and with reason) make Ts uncomfortable knowing one’s clients can know so much about them. I don't think anyone would like their private lives to be so accessible to all and sundry.

There is such a thing as respecting the privacy of others & it would be much better to ask these questions in person than to sneakily chase this up behind their backs. It is always possible to ask them point-blank and if they refuse to answer (which is their right), one ought to be respectful of this boundary.

The fact that this (still) bothers you is indicative of the fact that you are aware that what you did was, or could be seen as, questionable. In this case, it would be advisable to come clean to T otherwise it will always nag at you. It might also serve you better to address, with T, *why* there is this urge to get ‘inside’ his life so much. What need does it serve? What does it mean to know all this? How does it help you? Etc.