We hear you, and you're right. Most men are able to cover their tracks efficiently. Texts are easily deleted, and so is the browsing history. Stats show that over 30% of Grindr users delete the app every day only to reinstall it the next day.
The only possible solution to fully track digital activity is the use of device control solutions. We do not recommend this, as these applications are mainly developed for parents, and depending on where you live using them on your partner without them knowing can constitute and infringement of privacy.
However, if you do want to go down that road, you'll be amazed at what you can see. Not only text messages, Whatsapp convos and contacts, but also what apps are installed at any point in time, browsing history, keystroke tracking, photos, notes, emails. The works.
We've tried a lot of services, and the one we would definitely recommend is
Publicseek. They partner up with Spyfone, and the bundle of background checks, reverse phone lookup and phone monitoring they offer is great value for money (actually cheaper than buying Spyfone or any similar service on its own).
Good luck!