Does what the young man did, touching parts of a girl's body and inserting part of the head of the penis into her vagina without full penetration, constitutezina, despite their repentance and efforts to rectify the situation, along with his continued visits to her with the intention of marriage?

A servant's disobedience to his Lord by touching a girl, looking at her, and being alone with her, are preludes to the forbidden act of adultery (zina), and these acts warrant discretionary punishment (ta'zir). The act of zina that necessitates the prescribed punishment (hadd) is only fulfilled by the insertion of the entire glans into the vagina. The questioner must offer sincere repentance for this act and sever his relationship with this girl, either by marrying her if he is able, or by leaving her and keeping away from her. The questioner's inability to stay away from her is a sign of weakness on his part and a temptation from Satan.