The first symptom of Male Depression is denial. So is second one.

Men avoid doctors and try to figure things out alone. Then they self medicate. That can include substances, women, cars, etc. Depression is the fuel of MLC. Haven't seen reports here of MLC without it, except maybe for SF's H, according to him. I also question that.

Like Snodderly pointed out, you are both at a prime age to be questioning your second adulthood, and your readiness to leave your first adulthood behind. This includes concerns about career ... often peaking too early, getting sidelined, or laid off. If kids are around, they are likely getting older and independent. The "mother" is not needed so much and feels laid off from that job also.

If the H has had trouble at work or financially, she may not see him as trustworthy as in the past. Of course you had depression with all this going on. Then the LBH makes the worst mistake and begs. MLC-WAW sees this as really wimpy. Sees OM as strong and complimentary, strong shoulder to lean on. There ya go. Recipe for hell.

Hang in there and keep updating. The folks here have been through the grinder and will give you all the support they can.