I'm not sure I'm able to give you any solid advice, but if you'll listen to my rantings, maybe I'll be able to break it down a bit, if nothing else. Please also disregard any typos, as English is my second language, and I don't use it that much.
To me personally, it's natural to be friends with exes. Granted, my exes(and I'm 26, so that's honestly not that many) used to be friends before entering any relationship. We parted on good terms, and stayed friends after we broke up. I really woulnd't want it any other way. We had almost all our friends in common, and would have had to meet a lot in any case.
Whenever I have a problem I need to discuss with someone, I need them to challenge the problems, and I'ev found the easiest way people can do that is not telling me what is right, but asking me questions that makes me think, and discover what is right. In that spirit, I have a couple of questions for you.
- Can you trust him? As far as I can tell, there's really not any reason to believe he's comitting adultery or doing anything else he shouldn't be doing.
- If he still has feelings for her, does it matter? I guess this one is not so self-explanatory. Not being over the person isn't neccessarily a bad thing, it's what you make of it that decides how it will be perceived. For example, I will always have very strong feelings for the women I have loved, it's only natural, but I would never let that jeopardize anything. Maybe they actually are nothing but really close friends. In that case, you need to be fine with it
- What do you mean with "past scenarios?" I'm a bit curious about what type of scenarios these are.
In my opinion, they may be overdoing it. Not because I think what they're doing is wrong, but because you're not comfortable with it. That's something he should be understanding about. But you should also be understanding about he wanting to have contact with his longterm friend.
Honestly, when you ask if it's unnatural, disrespectful, intrusive and unnecessary, I'm afraid my answer to all of the above, is simply no, it's not.
Remember, an ex is just a bad thing if the ex is bad. What I think, is that they have a relationship you don't feel you can compete with. They have known eachother for years, and you don't want to come between the friendship. The good news is, you don't have to. Who does he come home to every night? For whom does he make breakfast in bed?(I hope he does! :O) Who does he buy flowers and take out to dinners? Who does he love?What I'm saying is, she is the friend, you are the girlfriend. She can't fill those shoes anymore, but you can.