How long does some one have to change their mailing address before Return to Sender can be put on it?

[chaysemanhattan]

My current mailing address is an ex- boyfriends address, for personal reasons, per a mutual verbal agreement. All the sudden he is claiming after 2 years, he is going to put Return to Sender on my mail with out any prior notice to me. Is this legal? I did live there for a couple of months, but this was 3 years before the agreement was made. He knows how to get in contact with me via my phone, work, email, Facebook, p.o. box and where I am currently staying. Due to a very unhealthy relationship, I recently decided to end it, and am trying to obtain property he also has stored at his address with no success. He is now threatening me with the above, because I said if I was unable to obtain my property, I would have to take legal action. He has not given me any time to address the matter above, and claims he does not have too. He currently has mail of mine, and refuses to give it to me. I know I need to address this matter right away, but what about the 4 to 6 weeks it could take per the USPS before that happens. Can he put Return to Sender on my mail till then. This could be problematic for me, and I know that is why he is threatening to do it.