Why is the suggested words part of my keyboard out to get me?!

[Android Central Question]

My fiance has synced my Google account to his new keyboard app that he just got. He typed his name and it then gives the 3 little boxes on top of the keyboard that suggests the next word. Well, his specific keyboard app he says highlights words that have supposedly been typed before in sentences. So he keeps clicking the highlighted words and forming awful sentences that are making it seem like I'm cheating on him and talking to multiple people badly about him, when I've never done either. This is ruining my relationship, making me look like a liar, a *****, and a horrible fiance. If anyone could help clear this up and help me to explain to him how and why it is so very incorrectly suggesting these sentences I would deeply appreciate it!!!