Living alone after separation/divorce

How difficult is it to live again after being with a partner for 13 years (married 10)?

37F here, will be separating soon from my partner bcoz of his infidelity. I know I am not scared per se of living alone as I have done this in my early 20s. Just that you get so used to being with someone and then to suddenly be all by yourself is just feeling odd.

Tell me how does it feel? Do you regret it or feel better? Has this thought not let you leave someone?