Waitwaitwait...
When did his Ti become weak?
When couldn't INTP's enjoy playing music?
Being jealous while denying the existence of the emotions sounds pretty INTP to me.
@OP
You mentioned you wouldn't take anything said on here for granted, I'm going to take that as license to splurge without restraint.
Okay so the love thing I completely understand. It's not necessarily that he doesn't think it exists at all, just that he doesn't think he can experience it. It's like when you're talking to a highly spiritual person and you don't think that they necessarily don't experience what they say they do, but you don't think it's something you'd ever experience, and you can sort of write it off as a subjective experience of those that are less rational.
This basically speaks of a drive to control the irrational within oneself, which is something most people on the forum can understand I'm sure. Basically he rejects his inferior function (Fe), allowing his Ti to reign tyrannically in service to the values instilled in him by his abusive father. You might find it odd that someone so rational could be so unsceptical towards his underlying motives, but given their source, it's not difficult to see why he might want to leave that stone unturned.
This man is completely untrusting. Relationships are not something he sees as viable, as he cannot split his intentions with another. I've had very very similar experiences where I'm happy to be around someone, and to be intimate at some level, but essentially hello always ends in goodbye. You look at the statistics behind relationship lifespan, and you see that really what feels so good now will almost certainly end in one of the most painful and miserable experiences of your life. It's not necessarily entirely selfish either, after all, you're the one with emotional problems who will almost invariably end up sabotaging the relationship through no intention of your own. By refusing to nurture such a relationship, aren't you saving both parties the trouble associated with relationship death?
Since he does not believe in love, he does not believe that an entity other than himself can serve his motives. When two people bond they pool both their resources and their goals, he doesn't think you will serve his goals, and he doesn't think he can serve yours. I don't know if he's wrong, I haven't met the fella (or you).
While, given the light that your later posts shines on the current context of your future, I think you should cut the chord, as he is unlikely to improve your life, I don't think you should hate him or start thinking of him as some sort of bad person. He's damaged, but not necessarily in a way that stops him being a good person. He's just not capable of providing for your needs. The portrait you paint of him basically depicts a nomadic musician, you are not going to be able to change the characteristics that underlies not only his relationship style, but his career and social style as well.