Seeing as you are 25, I will assume your boyfriend is the same age and so I'll be blunt: get the hell AWAY from any grown man who, despite having financial independence, doesn't have the balls to tell his parents he's found the woman he wants to get married to and does his best to make it happen. The fact he's still coming round to yours for sex tells you clearly where you are in his priorities - good enough to sleep with and not good enough to marry, despite your wishes. I get the impression that even he believes sex outside of marriage of wrong, yet he still continues to do it. Do you know why? Despite the fact he may genuinely like you as a person, love you even etc etc, fundamentally you are the easy option. He will marry who his parents select for him.
And I don't mean this as an attack on you, but I have to say - after you broke it off for 3 weeks and you called him back and restarted the physical relationship, this, IMO is a sign of immaturity. Maybe you missed him, you missed the attention, you missed the physical relationship, but a true partner is your strength, not your weakness. He can see that you are trying to become more religious, and he should be assisting you with your growth and wanting the best for you. He should not be happy with this situation as he can see you are so unhappy. But he wants it to continue regardless.
Again, really not trying to be horrible about this, but to me it sounds like you two need a break, a REAL break, so you can work things out on your own terms, and not with other people with vested interests influencing your emotions. Focus on another goal in your life apart from marriage - learning to pray, tajweed, or a career etc. Build a community of like-minded people who will help you achieve your goals.
You said in your first post that your bf told you his parents would never allow his marriage to you. He's said this clearly. Accept that this means your wishes and his are irreconcilable (and do you really want to be with someone who could never stand up for you anyway even if you did get married?).
In 99% of cases, if his parent's wishes are so important to him then he WILL eventually marry who they want. It will not be you.
I can't imagine how difficult this must be for you - 6 years is a good chunk of your life at 25. Insha allah I hope that things work out for the best.