Stop talking to him about Nick.
I didn't say stop your previous talking about Nick. Stop talking to him about Nick means, stop doing so from here on out. If he asks, tell him you're no longer talking to Nick.
Wipe nick out of your life , if he is the other side of the world , you met him on the internet and never in person , what's the problem ? i would advice you delete your profile for meeting people on the internet , that will prove to joe that you are only interested in him and not meeting other guys. Tell him how you feel about him . But be caucious if you have never met him before , don't rush in to anything. Because you can't be sure of your feelings as you have never met him and it is a virtual relationship.
Stop contacting Nick. Give your full attention to Joe. Joe is right in front of you. Nick is miles apart. Your choice.
It's been said a few times, but bears repeating - the more times you talk about the other guy, the more he's (quite naturally) going to assume that either (a) you have some reason to feel guilty about him or (b) he's constantly on your mind. Stop talking about him, and if the new guy brings him up, just say "nothing really happened, and he's out of my life now".
Bear in mind the possibility that "Joe" doesn't feel jealous (you could be imagining it because you think it's something to feel guilty about, which it isn't), but your behaviour could make him think he should be.
Hmm, by making him your boyfriend instead of a potential future boyfriend.
First, stop trying to contact Nick. If it was headed towards the end he'll know it's over.
Start trying to put Nick out of your mind as much as you can. Remember the fond memories and put the rest away.
Look Joe in the eyes, or as best you can given the distance, and tell him there is nobody other than him.
Then let it go. You can't change the way Joe feels and thinks. He has to accept that Nick was in your life, in some form, and is now NOT in your life anymore. If Joe remains jealous well, then, that's his issue to deal with, with your support.
Lastly, why on earth are you, at this age, even thinking about finding someone to be serious with?
Sorry, that was a bit harsh on my part. I know full well you can't help who and when you fall in love. I hope it all works out for the best.
Just be yourself, be confident with Joe and he'll see the truth.
Hmmmmm...... That's a little like asking how to make a guy not a guy.
But if he's not already mature & secure about such things, you might try being up-front with him about your feelings toward him alone, about your willingness to resolve any lingering doubts or conflicts in an open, respectful, but frank dialogue, and you can set the example by never being insecure or jealous of his past girlfriends.
Failing that, you can take your cue from my first line and either get a girlfriend, a gay male friend, or a pet. Good Luck!
Then you've done about all you can reasonably do.... and more than most would. Now all you can do is let things unfold. If you keep true to your words, and you both have the care & respect to treat each other honestly, you should be fine. Again, good luck.
I just think its gonna take time to prove your interest in him. You really can't make someone else secure though, that comes from within. Be honest no matter what you're feeling and let the rest fall into place...good luck with it :)
Don't mention the other guy again, and if Joe asks tell him you ended it.