Lala Kent Suspected Tom Sandoval Was Having Affair With Raquel Leviss In Summer

Lala Kent says she had a feeling something was going on between Tom Sandoval and Raquel Leviss before their affair devastated Ariana Madix ... with her suspicions dating back to the summer.

We got the "Vanderpump Rules" star at LAX Tuesday and asked about Tom bringing Raquel to his hometown back in December, when he was still dating Ariana.

Lala says the affair, which we first reported in March, was a shock to folks outside the reality TV show cast ... but she says she and Katie Maloney felt "something was off" months before Raquel visited Tom in St. Louis.

While Lala had her suspicions during the summer, she says Ariana didn't know Tom was cheating on her until March, when she was absolutely gutted.

The signs were there all along ... Tom and Raquel were rocking matching necklaces back in October, and she kept popping up at his shows and his restaurant, hanging out with him without their other cast members around.