Pee and poo accidents

[Booloo]

My little man 4y 8 months has rarely had a dry day in his life. He withholds day in and out but will hide in a spot and move his bowels in his pants. He also has regular urine accidents. We have had him checked and constipation was diagnosed ( mostly because of withholding) . He runs for a pee in the toilet multiple times a day but if he is busy he will wet . The wet pants doesn’t bother him and he denies ( even though we can see the wet patch) . He is adorable and very affectionate and his whole little life revolves around toilet talk. I’ve tried EVERYTHING. I remember as a child I wet and getting in trouble when I didn’t mean to do it.

I am a worried mother who wants so so desperately to help her child. I’m tormented to put it mildly.

We gave him senna and movical which worked a treat and I started reducing until everything fell apart again , how trying to get back to where we were ... but he still wet when we were on track ( only once a day ) that was the best we ever got.

Looking for advise or has anyone out there gone through this and survived ... I need to know we will get by all of this ...