My brain is blanking, do you know if he's still with OW? If so, I would employ the thanks but no thanks (the idea being Oh, you're still with OW? Then I don't really want anything to do with you). If not, I'd take it a gesture and take them. JMHO.
M:26 H:32 T:8yrs ILYBNILWY/ "I'm not happy": 2/6/16 D-Day-discovered PA/EA: 2/10/16 Separated: 2/14/16 He's living with OW I moved to different state: 06/16 Currently: Trying to move forward