OP - it can be really hard to disaggregate all the struggles, difficulties and disappointments in life and work out a way to overcome them. Daily life really can be engulfed in drudgery and lack a great deal of joy. However there can be a tendency to focus those frustrations on our nearest and dearest - and more often than not...on DP. And often they're doing the same. It means storing up resentments, a loss of intimacy, arguments and a loss of love.
Sometimes the distance becomes too great. But provided that things don't become abusive, or infidelity or mistreatment occur, then it is possible to reconnect. The first step is recognising that things should feel better, that there are probably faults on both sides, and that things need to change.
There are masses of articles, websites and books offering advice. But for now - I'd say don't imagine that because you are wondering, it must already be too late. There are so many stories of people who blamed their partner for their unhappiness, or who decided that the feeling was lost, who discover too late that their partner wasn't responsible for their unhappiness anyway, or that they'd just stopped seeing them as a person first. It happens.
So maybe stop seeing your DP as someone you are just hitched too, and start seeing them as a person with agency and choices just like you. And perhaps talk about the things that might make you happier. And look out some ways to start improving trust, intimacy, connection, appreciation, kindness, forgiveness. It's great you've started counselling, but sometimes these can become sessions that are divorced from the rest of your lives, as if you open a book, read a few chapters, and then close it shut and don't dare to discuss it later. It's meant to help beyond the sessions, and I hope it can. You need to talk properly, and maybe the counselling will at least help in showing how to to that. Your children are very little and it can be hard work, but all families need some joy - and you usually have to find it - it doesn't always come looking for you!