Its hard to help with such little information. You said that you probe with your front hand. Does this that you leave it out there and gauge distance thus providing that visible threat of range? If so, then are effectively taking control of the centerline at long punching distance. He will thus need to parry your lead hand out of the way or come around that lead hand to land the body shot. This is where your footwork comes in; step back and get that probing hand infront of his face again. A way to work this is simply to drill where your job is simply to push their face away to your preferred length whilst your partner is just trying to get past your lead hand and put his head on your chest. If he comes around your right jab to your right, then pivot by stepping out to the left with your right foot. If he comes around your right jab to your left, then pivot the other way by stepping your rear right foot behind your lead right foot. Very similar to fencing.
Or do you work your jab actively (also like you said) to similar effect? In this case you are closing your lead arm close to your body between jabs and closing off the option of that body hit. He will need to counter you with timing to hit you whilst you jab or before you have brought the jab back. The solution in this case is different. By pulling you lead hand back and protecting your body (as opposed to leaving it out in a probe), you make the threat of your range less visible. Therefore you can manipulate their perception of your range by throwing jabs at different lengths. Try subtly reducing the length of your jab so he will think he is at a safe range as he slowly comes in, then shoot out the long jab again, to hit him and maintain your dominance at long range. When he is doubting whether he is safe or not, he will probably start out a bit further to make sure he is safe, thus giving you more range to play with. Both this and the previous method can be done interchangable; it doesn't have to be either or.
Or do you just want to hit him from a safe range where you can't be hit? I suspect this is the case from your sentence about not wanting to put yourself in danger. This is VERY common amongst beginners and makes sparring very wild and sloppy. If you have longer range than him then great, you can interecept him as he comes into your range. If you are fast and accurate enough, you will stop him on the way through. If you have shorter range than him but fast feet then you can still fight at that range by quick entries and exits (I call this skirmishing). You can use different size steps/entry feints in a similar way to adjusting the length of your jab. If you are too slow or sloppy, then he will get past your range and make you pay (probably with a body shot). The way to fix this is to develop better confidence in your defence and greater sense of your range. You can do this by doing many complete defence rounds; only defend whilst your partner stalks you. You will notice your defensive skills will be immediately better when you aren't dividing your attention between defense and attack. Once you can sit their and have confidence that you can defend what they throw at you then you will develop better visual judgment for countering and then baiting to counter (as others have suggested).
As I previously said, it is difficult to give advice from the very little information you have given. You may actually mean either of my listed troubles though I suspect it would be a combination of all of them but maybe not using them at appropriate times (hard fought experience will fix that).
A little trick that you could use immediately, is to bait the body shot and then drop your lead elbow to block it. They wont like risking a body shot into your spiky elbow. You will also be in a good position to drop that left cross/hook into their face. Though with this, train with a less spiky elbow (perhaps 90 degrees) to protect your training partners (though they shouldn't be throwing hard anyway). Later in more combat-oriented situations you can just bend the elbow more and make that elbow extremely sharp for them to punch into. Kostya Tzsu used to do this to body punchers.