One almost valid reason a partner might say they "need space" instead of actually being honest and admitting to the real reason is if the partner is being abused. This could be physical abuse - but it could also be emotional abuse. If your partner was being harmed, teased, put down, not supported - all of these would be reasons they would want to get away from you. They would be quite valid reasons.
There is never a reason that a partner should not be fully supported by their partner. If you felt your partner had faults and that it was OK to pick on them, then your partner deserves to go find someone else who appreciates them the way they are.
If you have been abusing your partner in ANY way then it is your duty to first apologize profusely for it. You as a partner in a relationship have a duty to support, help and love your partner - never to be an active negative influence in their life. You must then promise to be fully supportive going forward, if you want any chance to be with them.
Now I'll add the caveat in here that if they are abusing drugs or alcohol, this might be a reason that you are not thrilled with their lifestyle. Your duty here would be to help them get better - just as if they were sick with any other disease. You have to do that in a SUPPORTIVE way though, not in a mommy-like nagging way. There are tons of websites out there that can help you do this task.
This tip was submitted by an anonymous visitor to our website.