I am a complete beginner to the sport and bought a Trek Mdone about two months ago.
I am able to train up to 90mins but after this point I get all kinds of numbness in my groin and have to stop cycling.
Any ideas why this is happening??
Sub 39min 10k Run
Sub 50min 2.5 Km Swim
Training Blog - Winter Running Jackets
It's a common injury. If you continue you'll likely end up with having erectile difficulties. Your bike seat is the likely cause, it puts pressure on the nerves and blood vessels that supply the groin/penis.
Look for a "no nose" bike seat.