I've had similar problems in my own marriage. I was overwork, stressed and depressed. There could be a reason for his behaivor. Is it a recent abrupt change or has it been getting worse over time?

Every marriage needs that certain connection and intimacy. When it is missing it feels like you are staying with a room mate.

Another cause could be an affair. Been thru that too. She become more distant while it was going on. Things blew up when I found out and after some marriage counseling things are better.

If it were me in your shoes I would make him sit down and talk. It will be hard but a face to face discussion is probably the best way to get it out there and to work on whatever may be causing the issues between you too.

Is it possible he never saw your email? Avoidance is another thing people do a lot especially with things they can't cope with. They just pretend like there isn't a problem and do what they do.