Kathleen It may not be mlc. Read the resources at the top of this forum and you will get a better idea if it is mlc or not. What makes you think it is mlc?
Going to dinner at his place is okay but hold no expectations if you go. Just go as a friend and expect he will probably withdraw after.
Now it is time for you to work on yourself. As long as there is ow then then there is no possible reconcilliation. I am not saying to d but if he is still with ow then no r talks.
So concentrate on your own life while your h gets his together.