I have been talking to my ex of 3 years again but I'm hesitant if I should be giving him my time?

Why did you break up in the first place? Is the reason why you broke up still relevant? For example - if you broke up with him because he was unfaithful - has that changed? If he has not changed, what would be the reason why you would want to be with him now?

If things have changed, do you feel comfortable with the changes? If you're not sure, then go on a semi-date with him, such as movies or dinner. Don't be intimate, if you were before - take sex off the table until you know where you stand. If the date went well and you feel comfortable in continuing, then go for it. Trust your gut feelings on this. If it doesn't feel right, don't continue just because you miss him.

That would depend in the context of your newfound relationship, how important your ex is to you, and of course, your past. Did you end on a good note? Were you close before you got together?

Why did you break up and how strong are your feelings for him now? Since you're hesitating then there must be part of you that's not comfortable with him being around again.

Go with your gut feeling and listen to what your common sense is telling you which sounds as though you don't want to get tangled up with him again.