He can’t make up his mind!

What should I do about someone who can’t make up his mind whether he wants me in his life or not? We used to date months ago, and I told him I had feelings for him, but he brushed me off at the time saying he wasn’t looking for a relationship. A few weeks ago, he reached out asking if I would like to go out. I wasn’t sure, but we met, and he said he was confused about me. He wants to meet again, but I don’t know how I feel about him anymore. What if he has changed his mind because he hasn’t found someone else? I don’t want to feel like a back-up plan. Should I just block him and move on with my life?
You haven’t asked yourself how you still feel about him, which is all that matters. People change their minds all the time and sometimes take a while to figure out what they want. To assume the worst and call yourself a backup plan is unfair to you as well as this person, because you aren’t basing this on factual information. Why not think about what you want, meet him again, and ask him direct questions about his confusion, why he has changed his mind, and what he feels? If his responses aren’t satisfactory, you have every reason to give up on this. Do it only if you still consider the possibility of having him in your life. 

I haven’t met someone I used to date in three years, and we are going to meet in a week. I don’t think I have gotten over the end of that relationship and will give it another chance if she still likes me. Is this a bad idea, given that so much time has passed?
You are allowed to feel this way provided she reciprocates, and you won’t know that until you meet. Why not assume this is just a friendly meeting, avoid putting pressure on yourself, and see how the evening progresses?