A-First of all, don't drive yourself crazy trying to catch your partner. Decide to trust them. I always tell people, the scum rises to the top. If there’s something scummy, you'll find out soon enough. When you feel distrustful, you’ll be acting that out in some way and it will damage your relationship.
Secondly, do you suspect your partner is cheating or do they have a history of infidelity? In other words, are your insecurities based on facts or your own past experiences maybe with other partners? It’s not fair to hold your current partner liable for hurts done by someone else so make sure that’s not the case.
Lastly, take this as an opportunity for self growth. Manage yourself through the discomfort of suspicion and jealousy. If you need help, get with a professional!
Hope that helps!