I may be miss-understanding what you are saying, but no.
You have two separate things going on. First you are powering the controller, which like any electrical circuit requires a positive and a negative (hot/neutral, hot/ground), and a control/thermostat which is only a switch that tell tell controller to turn on.
In your drawing, you have power(R) going to the controller, but you are breaking the other half of the circuit through your relay. You need to add a wire. You should have R to the 24 terminal and C the the 24 gnd. Then a separate wire coming from R through your relay, then to TH-W.
Think of it like a light switch, it doesn't mater which side of the circuit you break, when you break it there is no power. If your controller doesn't have power it wont work. You need both the R and the C to the controller, then the TH-W is just an enable disable based on temp
Also, the ignitor ground, must actually be grounded. You ca run a wire to the ingitor and ground it, or you can run a separate wire to ground, but it must be grounded.