In science, there is no diagnosis of "midlife crisis", but many at the age of 45 - 55 notice complex psychological experiences in themselves. A person can be haunted by thoughts of old age, illness and even death. These are truly challenging existential experiences and a challenge for our ego.
But it is important to remember that a critical condition, taken under control in time, will definitely end. A crisis is the very time when self-respect plays a major role.
symptoms of a crisis include:
1) excessive self-criticism;
2) devaluation of the past;
3) harsh decisions, rash actions;
4) depressive episodes;
5) fear of the future;
lack of goals;
6) aggravation of bad habits;
7) excessive fear of aging, illness and death;
8) a general deterioration in emotional life.
The question is: how will you cope?
Be careful with yourself: do not blame yourself, do not get angry and do not scold yourself, fate or your spouse. The life situation has developed in such a way that you have come to this point. A cold-blooded analysis of causes and consequences will be much more effective and honest. You need to live emotions, but it is not your fault specifically.

Time will pass and everything will get better! And most importantly, remember: adult men are much more popular with women! I hug!