My DH has been married before (ended years before I met him), they met when he was 20 and married a year later. However, she was over ten years older, and acted much older than her actual age. The marriage ended after only a few years, he moved to the other side of the country and I met him.
He has always felt guilty about not succeeding in his first marriage and his ex has had difficulties letting go. She has never met anyone else, hasn't any friends (DH says she falls out with people easily) and her elderly parents have both died. She regularly calls and texts DH , has added him as next of kin in her will and a few years after DH and I met, asked for her wedding ring back. She had given it back to him when they separated, it is quite valuable so we assumed she wanted it as an asset. However, she is wearing it again.
She regularly asks to meet up with DH, I have met her once and DH has met her a few times. I, obviously, would be more comfortable with him not meeting her but I do feel sorry for her so just put it down in my mind to the equivalent of meeting up with a maiden auntie.
DH and I both have extremely hectic jobs, children that keep us busier than busy things and very little time (or money) to spend quality time together. He asked a week ago if he could meet up with his ex this weekend. I was a bit  as it has been well over a month since we have spent a full weekend together due to work commitments, children needing to be different places etc. I said it was ok as she has been badgering him for a while and thought I can take advantage of him not being there and have a duvet day with the kids. All fine, not ideal but only a small bit of a larger picture and not worth worrying about. However, I asked this morning, as I was heading out the door, where they were meeting and they are meeting in a lovely tourist town and spending the whole day together! I was a bit taken aback and just said, "you're taking her on a date?!" but couldn't stay any longer to have a conversation.
AIBU to feel really, really jealous? It has been a very long time since we have had a day out, just the two of us and I have never been to this place with DH. I do trust him, and know he is just trying to be nice but feel he has really overlooked my feelings in all this. I know his sisters and his mother would think he is being unreasonable, but we get on really well and they didn't like his ex. My green eyed monster is wanting to have an argument but the rest of me is saying to just be the bigger person. I do feel a little jealous when DH has contact with his ex, would be strange if I didn't, and I do feel a little envious when he goes somewhere nice without me but this has given me that awful knot in the stomach feeling.