My baby daddy, who is also my fiancée, lives in a different town. Although it’s a long-distance relationship, we’ve managed to make things work and have never had trust issues until a few months ago when I asked him to give me the password of his phone or but he flatly refused and ignored all my requests after that. This has caused me so much stress and caused a huge strain on our relationship. So much so that we are thinking of parting ways. Am I being petty or is he the one with issues?
By the time you get to fiancé level, there must be some level of trust that I assume has already been attained. My rule of thumb is generally it's a bad idea to go through someone's phone, because you'll find what you're looking for. Anything in a different context can be misconstrued, so since you don't have the benefit of knowing the people your fiancé knows away from you, don't bother.
You're never going to like what you find. If he wanted you to know, he would have told you. If he didn't, he's still not going to tell you whether you like it or not. Not everyone has something to hide; sometimes it's just the sanctity of privacy one values.
And, surprise! You don't have to know everything. A password shouldn't be enough to break up with him – if it is, your problems are much nicer than most.