Bright - I'm no vet or 'expert', but I'd just say 'You're welcome' and leave it at that. I know I am guilty of overanalyzing e-mails or texts I get from H, and sometimes it's just clearer to those outside the sitch what might be best to do. With a simple 'you're welcome,' you're both being polite, but that's really about it, nothing more, nothing less. Seems appropriate for the circumstances. Just my 2 cents...
Me 53, XH 57 M 20 (+1.5) years, no kids BD June '13 H moved out July '13 Confirmed long-suspected PA Feb '14 H filed for D Nov. '14 D March '15