Have name changed so can't be traced to other username, I'm not a troll/liar/sensationalist etc. Have been here for years, was here when Mexican House thief was active, saw penis beaker develop, have eaten naive ham etc. Loved the multiple threads about the listed building being changed by new owners and it causing problems and the OP and their Spanish Grandma? (DGM became unwell though, and there was mention the scenario wasn't real, did it even get found to be real or not?)
Many years ago I needed to send an e-mail for dh (he'd asked me to) while he was at a meeting. My laptop was off and his was on and as we would use each others anyway I just used his. Upon opening it his Messenger thing was open and it was blatantly obvious he was having an emotional affair. He had been using his laptop a lot, but worked from home so I wasn't suspicious before.
I checked and there was evidence of an emotional affair with two different people. (They claimed to be women but online you can't be sure if you have never met them irl.)
'Discussions' were had, help sought from third parties etc. and things put in place to get through it. E.g. dh agreed to let me check his computer/phone etc. with no prior warning, trust was gone and needed built up again. Over time I started checking him less and less.
A couple of years later, after changing jobs so now working outside of home, he became more into his laptop again, he'd sit in the car park outside our house for a few minutes after coming home from work not realising I knew our car engine sound and could see he was back, he was using his phone in the car while parked etc. Instead of only using texts/MSN/other messaging service he was mainly using the chat option in an online game (one to one, not to many users) and having an emotional affair with at least two 'women' again. He'd often put his mobile face down so I couldn't see the screen if I unexpectedly walked into the room he was in, he became withdrawn etc. I deliberately went on his laptop and checked as I just knew he was up to something. Confirmed my fears. Things blew up. We should have divorced. He got help and we worked on our marriage. Because of this it was going to take much longer to get to a trusting stage etc. I made it blatantly obvious if it happened again he was out the second I found out. He promised to try to not do it again.
He made sure I knew what he was doing on devices, he gave up his privacy on them willingly to show he wasn't doing things wrong again. Unfortunately I can't, and shouldn't have to, check everything. A few months later, on the online game, he fell back into chatting inappropriately with the two 'women' again. I found out within days and told him to leave. I saw him change then and there before me, a realisation came over him about what he had risked (a bit too late for my liking) and he sought help from another source. We are, a couple of years later, still working on our marriage. He has changed though, but I still look for 'signs' and check all his devices randomly.
When I became suspicious had I not checked his laptop/phone he could have kept up these emotional affairs for a long time and our marriage would have been over. Because I 'snooped' and found out early, it was nipped in the bud quickly and our marriage has one last chance, if I had not snooped I would be forever suspicious and that is no way to live.
I have promised him if it happens again there is no way back and he is taking me at my word. Someone helping us is also aware of my promise to him and will support me to go through with it if needed. He has also promised it will never happen again, not promised to try to not do it again like his previous promise.
In a nutshell - When there are genuine grounds to be suspicious I think you need to check up on the other person. Either you are proven right and can take measures accordingly or you are proven wrong and you can adjust your thinking accordingly. If you don't snoop you will be forever wondering if there is something wrong and the suspicions will take over your life. No one wants that.