The father of my child is with a new partner over a year, they live together and during the summer I agreed that the one night a week he has him he could have her in his partners house. On the basis that he never sleeps in their bed and my partner doesn't sleep in our DS bed (he comes home looking for me to sleep with him if his daddy does). I asked my son 3.5 if he'd slept on his own when he stayed in his dads the night before and he told me he had slept with his dad and his dad's girlfriend. To me this is totally inappropriate, I've welcomed her in my sons life, text her to thank her for presents she bought him before BUT this I am not at all comfortable with. So I addressed it with my ex, who said he will do whatever he likes when he has our son. Now considering I work full-time as well as my ex and the responsibility of looking after our son lies with me 6 out of 7 days a week, I potty trained him, organise his childminding when both of us are in work and he's a smart, kind lovely boy (mainly down to me). I feel my ex only has to feed and bath him once a week, I send spare cloths (dad has none) and because of how little responsibility my ex has he should respect my rules and my sons mother? Do you think I'm wrong?
Also, my ex told me many times he would leave his current partner if I would have him back so it's hard to take their relationship seriously.