i'm 18 years old but i'm much mature and i've had very interesting and fullfilled life in every field of life,i had beated,with help of the psichologyst, some kind of depression,anxiety and other psychical problems that were destroying me from inside for a very long time,since i enter the puberty.now few problems are left that are devouring me

i have a girlfriend from other city for 2,5 years and our relationship is based on trust,we are seeing each other very often,almost every week.. well the first problem is my possessiveness and jelaousy,i really don't have a reason to be jealous becaous she is the tipe of girl that every man wants,before me,she hasn't kissed anybody,no one could have her,and she is really sexy,but real lady,and her behavior is perfect,but i can't  submit some things such as a dress or t shirt in wich she looks hot,or a picture on instagram that is sexy,to understand she doesn't wear leggings or hot short dresses or decolletage but i have some dissorders and i'm jealous anyway when she looks sexy and i'm angry and we are fighting over that for a year almost every day till now,now she can't stand it anymore and we broke up,that is one problem and well when i mentioned that i will tell one more thing,really ironic to my jealousy,sometimes when i masturbate it turns me on when i imagine that she is cheating on me or something like that and sometimes i can't help it

the other problem is what to choose,spend the whole life with the person that i love or having fun and sex with other girls while i'm still young,because it lures me,i'm often turned on and i'm also very atractive so other girls want me,but i've never cheated on my girl,never flirting,never anyithing like this,i'm completely loyal to her,but that feeling is ripping me off,i want that feeling to get out off my life,i want to spend the whole life with her and when some sexy girl wants to drag me into bed i want to say no and be peaceful with that,without uncertainty and that bad feeling that is devouring me

thank you in advance,i will appreciate any kind of advice or opinion