Hi there,
the squeeze technique for premature ejaculation is pointless, I feel. The two main reasons ejaculate prematurely is poor muscle control and psychological reasons.
Sex is such an intimate thing that if a man has an issue with intimacy, ejaculating quickly is a quick way to break the intimacy. It is also a quick way of avoiding "letting oneself go". Anxiety, stress, fatigue, all these things can cause premature ejaculation. If these things are rooted in his past then, yes, they can be worked on in therapy.
From a physical standpoint, he needs to work on strengthening his pelvic floor muscles. The easiest way to do this is to break up a pee when urinating. Initially do it once or twice during the pee, and build up to eventually being able to literally drip the pee drop by drop. The muscle gets built up very quickly. There are loads of things on the internet about it. Also, it puts him in touch with the sensations down there.
The key is to know that there is a point of no return, beyond which he will ejaculate, no matter what, a few seconds later. Learning to recognise this point, and sharing it with a partner, is a big step to helping the problem. He must feel confident enough to say slow down, without fearing that you will have a problem with that. Even if he has to come and and start again, at least he has recognised the point of no return.
For the rest, I guess there are just some people who are better lovers than others and, as with many things, a lot of that comes from experience. If, like you say, he came from a very repressed house and didn't have the experiences of adolescence, it is likely he is just very inexperienced. And when you add this into his confidence because of the prem issue, it is not difficult to see why sex may not be great for you.
Being with someone who lacks experience is not a problem per se. As long as either a) both partners have a similar level of experience and similar needs so they grow together as lovers or b) the more experienced partner takes the lead, shows the way and the other partner grows in confidence with that. That can be a lot of fun for both sides.
The fact that you are actually having sex is a good sign. The prem issue can be worked on and improved - and hopefully his confidence will improve with that. The more he relaxes, the more he will trust you, the more he will be open to new experiences. You can take the lead on that - maybe introduce some porn to watch together for example.
Hope that helps.
[I'm a man by the way]