I can understand how you feel. So, with that being said, sit down w/your h tonight and have a calm discussion w/him. Lay out the fact that you are not comfortable w/strangers (to you and your son) being in your home when you are not there. Keep in mind that he very well may advise you that it is his home as well and he will have whomever he pleases over at any time, i.e., just as you can. The bottom line is that you have to remain calm and don't accuse him of anything (as you have already done so). When you accuse him of stuff he becomes defensive and lies even more. You'll be able to better judge whether or not he's truthful when you are talking to him. Watch his behavior.
My question to you is this...are you prepared to hear his answers? What if they aren't what you want to hear? What is your strategy then? Whatever you do, do not make idle threats. Whatever you tell him in the way of boundaries, stick to them.
Stay calm and try to keep your emotions in check. The calmer you are, the better. Good luck!
