ReallyLost,
Sorry you find yourself here, but hope we can help.
It sounds like your husband is checking out of the marriage: no sex (1.5 years is a long time! I get to feeling left out when we got two weeks without and we’re almost 70!), him chatting with men online; telling them how unhappy he is with you (so sorry); and asking them how to fulfill his other side. It seems like he’s ready to do just that...fulfill his other side, and it doesn’t sound like that’s something you’re on board for.
Like you say, you’re broken. You need to be whole for your son, so take care of YOU. You say it’s time to move on. Perhaps start taking steps to do just that. Therapy may be a good idea to have in place as it isn’t an easy transition in life. get yourself a support system. If you don’t have anyone in person, post here..Even if you do, post here...as often as you need.
Best of luck I wish I had more to offer you. If things change, let us know. Keep us posted if you feel like it.
(((HUGS)))