OK raising children alone is hard There are others who did it longer than me. It helps to remember that widows/widowers have this task too.
Sometimes/often it seems like too much, but if you keep going it becomes easier, and now they are grown, I am so proud of them.
When there is no-one else to help and support, child raising is hard, but also a privilege. Not sure if this is helpful except that I am through to the other shore, and I would not have another relationship on any terms. I love my independence, and cherish my occasional loneliness.
Great if you meet someone else, but raising your children alone, while hard, brings great rewards. Accept help when it is offered. You will be fine. your spouse will not be, sadly.