Sharing Our Innermost Thoughts

I am very sad and confused. I am in a serious relationship with a man for the past two years but I am not sure if I want to marry him. He is very kind, affectionate, loving and charming. Apart from this, he is also very serious about his work but despite his dedication and hard work he is unable to make it big (although I have faith that he will). Now, I must also mention that he is the sole breadwinner of the family with 3 dependent members and so, sometimes, he is unable to make ends meet. Often he borrows money from me albeit with a lot of shame and guilt. So far, I have lent him what I would make in 6 months. Now I know that he really needs that money but I can’t help feeling sad over the money that I have lost. He says that he will return me all that money by buying something expensive for me but honestly, I just want the cash. I earn quite well and have no liabilities and so I would have saved a huge amount by now had I not lent him the money. I feel very guilty for letting such thoughts creep into my mind but I can’t help it. In the long-term is this a red flag? He had also borrowed money from me previously but in lieu of that, he took me to an all-expenses-paid trip to settle the score.
Secondly, our cultures are very different. He belongs to a lower-middle-class family. His family members are not so well-educated, he is the most educated member of his family. This clearly reflects in the way their household runs. On the other hand, I come from an affluent family. Both men and women in my family are highly educated and this is quite evident from our mannerisms and social conduct. Now the question that looms in front of me is, “Will I ever be able to adjust in his family?” With all due respect, marrying him would be a downgrade for me both socially as well as financially. Is it wise to make such sacrifices in the name of love? Will I ever be truly happy in their family? He assures me that his family would be very supportive of my career and they would shower me with a lot of love but I feel that I would really be out-of-place in his family.
Lastly, he is 4.5 years older than me and yet I am more successful than him both academically and financially. Now neither of us has a problem with this but my family would certainly raise this point for which I have no comeback.
With all this being said, I would like to emphasize that I really love him. I have gone to great lengths to prove my love to him. He also loves me a lot and even says that I have settled for less (saying this takes a huge heart). He wishes to reach my standards (academic and financial) and is ready to put effort for that but he can only change himself and not his family. Our future plans and goals align with each other, and he is very serious about marrying me. But marrying him would mean a compromise on all the above-mentioned grounds. My question is: “Is it really worth it?”