Proving adultery

1. Can we prove adultery on the basis of the fact that the subjects were often together and alone? What can be the exact basis for proving adultery?

2. Secondly, if I am only able to hint at a relationship, what benefit can I expect in terms of alimony, etc.?

3. Is there a way that the mobile company can be directed by court to produce evidence in terms of incoming call details and SMS text, etc to prove the affair?

Thanks in advance!