Re: I'm obsessively suspicious of my fiance
You can't necessarily control who texts you, but you can control not responding. If he had a lot of "baggage" before, getting the new number is at least a clean slate. Deleting texts does indicate he has something to hide, but if he tried to be open about the texts before when you inquired about them and you obsessed over them, then it sounds like he was trying to avoid a confrontation.
However, I agree with writeleft. You should give yourself time before you commit to a marriage. If you have serious trust issues, you need to resolve those before you make that kind of commitment. It will destroy any relationship you enter into.