Long Distance Relationship advice please?

Hi there, I am currently in a Long distance Relationship with a girl who is 23 and i am 24. she used to live in my city but relocated back to her mothers 86 miles away (2 hours drive). shes busy during the week working and we both have weekends but i am a student and i need to work 7-8 hours whenever i like at the weekend...i make my own hours. I plan on graduating and next summer moving near her. I know i am going to find it a bit of a strain every weekend to travel to see her so we agreed we stay over once a week rotational she come here and i see her. our parents are fine with it but our parents are retired. We will not get the chance to do our romantic stuff although things have been done at hers when her mother down stairs. Will she lose interest in LD relationship? I am in fear she will meet some one else as shes is very attractive. We keep in touch with texts and calls and visits...i went to meet her mum last week and saw thier house, we are both keen but how can i secure us?