1984 Dodge Ram Cannot Get Truck Start Key Cross Ignition Engine Will Crank

First of all, what's the symptom? "Doesn't start" can mean a dozen different things. What are you "crossing"?

my boyfriend is crossing the ignition switch, when he does that the truck will start. The truck will not start if we use the key

Chances are the ignition switch itself is bad. That is what I would check first.

We have replaced the ignition switch twice and the truck still will not start with the key. Everyone I have talked to says that there is a starter selonoid relay switch that may be bad, so my question now is where would the starter selonoid relay switch be on my 1984 Dodge?

There should be a power distribution box under the hood that holds relays. That is where it should be.

There's no need to go looking for anything else if he's connecting two wires right at the ignition switch. You know everything else is working because it cranks. That switch is adjustable and it's likely misadjusted so it's not moving far enough.

Also, look at the old switch for signs of blackened or overheated terminals. Of there are, you'll find the same thing in the connector's terminals. Those will need to be changed. If the connector body is melted, the terminals can be cut out and replaced and plugged in individually.