I think it's great if Linda can have her ex there, so long as he respects her boundaries. I would be willing to bet Dave was deliberate in creating discomfort and pushing her buttons.
I think that's a bit of a stretch and I'm not getting that from the OP at all - to me it sounds like Dave deliberately tried to stay out of the way a bit so he wouldn't push any buttons. Linda was the one who was displeased at the situation; perhaps it showed more than she intended it to and it was obvious that he wasn't welcome, but he didn't want to leave because his daughter had specifically said she wanted him there, so he did the next best thing he could think of.
Barring a situation like domestic violence - in which case would Dave have access to the little girl anyway? - I do think two divorced grown-ups should be mature enough to be able to deal with each others' presence in the event of a child's birthday if that's what the child wants.
It doesn't have to be just domestic violence, though. There could be more subtle forms of abuse. It could be any number of rel@tionship dynamics, and if one parent does not want their ex there, I'm going to lean in the direction there is a valid reason why, and not just being petty and vindictive and immature. For parents who can continue to co-exist in this way, I'm a little jealous. It won't happen for me. However, for school events and other activities, we sit together and share air space and perhaps get ice cream afterwards, but I will not have him in my home until the day comes we're dealing with graduations and weddings and grandbabies and holidays with adult children. I can manage that, I'm sure, but not now.
Interesting your completely opposite point of view of Dave's intentions. It makes sense, but he pushed the envelope quite a bit. If the plan was to spend time with his daughter, hanging out in the living room would not accomplish that. Dave will have to work on his boundaries as well, if this invitation made him that uncomfortable.
I'm sure you're speaking out of your own personal experience, but your two statments contradict each other. If you want to give Linda the benefit of the doubt in why she didn't want Dave there, that's fine. But, I think in that case, your argument should be based around giving Dave that same benefit of the doubt that he wasn't purposely being petty, vindictive, and immature.
He was rude to go inside the house..this is true. But that doesn't automatically make him petty and immature.
And spending some time in the house, while wrong, also doesn't automatically mean he wasn't spending anytime with his daughter. That's an ungracious assumption. He may have been trying to get out of the way while his daughter was playing games and her mother was organizing them. The OP did say that's what was happening while he was inside. Granted he could have just moved to another part of the yard and observed the games from there, but not making the 'best' or even 'correct' choice in that time, doesn't mean that he was neglecting his child the whole party.
Yes, my own experiences color my thinking, and this includes my mother's behavior to my father growing up, which could be considered immature and vindictive, which is why I have done everything in my power to do things differently, but the buck stops at hosting him in my home, even if it's my child's birthday.
It's not necessarily a contradiction if point A leads to point B, and this is why Linda does not want him around when she can help it. So I'm going to expect that Linda has a reason beyond immaturity for not wanting Dave around, and Dave snooping about and making himself at home is part of that reason, so not a contradiction. The reasons go together.
Yes, I leaned in a more negative direction on Dave's intentions, but I don't know these people, so all this is, is my own thoughts, and not necessarily reality or passing judgement on Dave or Linda...it's generic.
What I take exception with, is this idea that a person is less mature for not allowing the ex-spouse to stay for a child's birthday. I think that if the couple can manage this and continue to socialize around their child's special day in this way, that's great, but not allowing the ex is no different than excluding any family members from events that we see come up on this board frequently without considering that person immature.
Pam should not have asked her father without clearing it with her mother and this would apply to anybody. Because it's her dad, it puts a different spin on the situation. Because the day was split, she might have felt some guilt at excluding dad, which is perfectly understandable. She probably doesn't realize that daddy understands and daddy really needed to pick up the slack here and let her off the hook. He is, after all, the grownup. I would not have allowed him to stay. I have historically been left to be the bad guy.