F/30 m/32 how did you know your spouse was cheating before you found out for sure?

Things have been different he’s been distant and we haven’t been intimate. I can’t tell if I’m just paranoid or what he’s been kinda weird with his phone but, he swears he would never do that. We’ve been together almost a year and live together. Most nights I wake up alone and he’s in the bathroom. I feel so alone. What are some things that rose your suspicion about your significant other cheating but, you didn’t put two and two together until you found out for sure? What were key things they did that made you suspicious of cheating whether it’s sexting, emotional or physical? How did you find out your spouse was cheating and lying?