What do I do? Please help.?

I am 29 weeks pregnant and my husband and I are going for weekend vacation tonight. I found out from a common friend yesterday that my husband's exwife is moving out of town on monday. She invited her friends and my husband for drinks on sat. night, obviously my husband cant go because he is going for a vacation with me. My husband and his exwife claims that they are friends, when i had objection about their friendship and so called meetings, my husband (atleast thats what i think) stopped meeting her and we never discussed her again in our lives. Everything is going great between me and my husband and we have never been this close. I read his email and found out that he is meeting her today for coffee at 1:30, my husband probably didnt tell me about this meeting because he knows i wont like it. Now this is bothering me so much that I dont know how to react when he picks me up from work to go for vacation. If i confront, it will be a fight and disappointment and ruined vacation. Help?