Hello, I'm sorry, unfortunately I can't suggest any books, but i can offer some advice.
I'm a step parent and my relationship with my stepson changes all the time. I always love him, but sometimes we're close and other times we're a little distant. What we do have is a strong bond which allows our relationship to change whilst still feeling like a family. Two things have been really useful are:
1. Changing tact
- making sure I concentrate of being more of a grown-up friend, rather than a 'disciplinarian'
2. Quality time
- spending a little time each week doing something only he and I do together. Each week we cook something. whether its breakfast, a cake, dinner, etc. Thats what works for us, but you partner could do something a bit more 'boyish'. Like build a lego car together (or something more age appropriate!)
It's all about getting to know each other :)
I hope this helps.
Delilah. www.stepchildren.co.uk - the practical guide for step parents.