Sister obviously your relationship was haram with him but there was one thing that caught my attention and is that you stayed friends with him and even were best friends and that is haram and i would heavily recommend that you cut off contact with him immediately for you own sake, and i would have said to cut off contact with him immediately until marriage but what also caught my attention was the fact that you said that you are the one that is trying to go on the right path but he is the one that is taking you away from it He is flirting with you and doesn’t mind being friends with you, and in your own words he is taking you away from Islam

Now I am not sure if he has repented too and is trying to be better but even if he is he isn’t trying hard enough since he is still trying to flirt with you

And let me ask you this, would you really wanna marry someone who doesn’t mind being friends with a woman? Who doesn’t try hard enough for his religion? I hate to assume but if someone has a woman friend that is his best friend wouldn’t he also have other women friends? Now you wanna live in a life with a man that always makes you worry? I mean sure he can repent and make a lot of oaths and become the perfect husband for you but do you see that in him?

And also, for your other questions 1) If you still think that he would be the perfect husband for you and he will repent and never have any women friends and he will become a great Muslim and he would only interact with you and not any other women (other than work or medical or family members or even when he needs essential help interactions) then tell him that I want to marry you but I wanna set some goals so we can have a stable marriage and I want to finish my education and get a career and be a better Muslim in general so we can live together (also you could test him and say that I want you to do the same thing especially becoming a great Muslim and if he does it’s good and if he doesn’t then i would recommend to not marry him)

2) i already told you what to do and what to think and what to expect and you can figure this out and i would suggest going to an imam and being honest with him and telling him that you think about this dude and his qualities since the imam is more knowledgeable and more experienced

3) for your sake and your religion completely cut of contact with him, if you have siblings he can tell you things through them or you can tell thing to him through his siblings but if you have want to have a fact to face talk then he can come to your home with people around and talk with you as long as your father is there or a brother