Ryan Seacrest Enjoys PDA with Girlfriend Shayna Taylor Poolside in Miami

Ryan Seacrest seems like a man headed for a church, because he's in a relationship ... hook, line and sinker.

Seacrest and GF, Shayna Taylor, were showing full-blown PDA poolside in Miami Saturday, and it's apparent why she floats in his boat.

Shayna and Ryan broke up a while back but got together again,and are now living together in New York ... where he moved to do "Live" with Kelly Ripa.

We're smelling a joint tax return in the not too distant future.