Just to give another perspective my story is this.
When ex-wife left me our DS was 16 months. 4 months later not only had she introduced DS to her new BF but he was buying ex-wife a birthday card from DS as well as himself - though to be fair I always got the impression ex-wife wasn't all that impressed by this and DS was way too young to understand or care - suspect card from DS was just well meaning attempt by new BF to be nice to ex and show what a great Mummy he thinks she is.
Around that time I did ask to meet new BF, not to "approve" him but just because:
- I'd quite like to have some small idea of who someone else is whose spending regular time with DS, not sure that's unnatural or over controlling - and when we discussed it made that clear to ex - i.e. I don't want to do it to run rule over him, that's not in my control
- From a practical point of view it would have made sense - ex-wife was still in marital home, I'd moved to unsuitable place for contact time to help out with mortgage while we sold house. Two nights a week I'd pick DS up from nursery and go back to marital home to so I could do bedtime routine with him. During this period (some months) BF was driving ex-wife home just after DS bed time, dropping her off, then doing one until I left and presumably coming back again about 2 minutes later (he was using her car so it would have needed to come back for her to get to work the next day). So I just thought if we'd met and said a grunty hello at least they could both arrive home together as I left, park the car and get on with their evening! Still if he was that keen to avoid me fair enough - suspect drama of that potential meeting was somewhat exaggerated in ex and his minds.
Anyway another couple of years down the line marital house now sold, ex moved in with BF and I still haven't met him, even though DS (now 3) frequently articulates lots of things he's done with Mummy and new BF.
In that time I would say I've learned to cope pretty well with the situation, because there is no choice. But I am still curious as to who this man is. Anyway when I mentioned DS now talking about him quite a bit ex told me that new BF "takes a back seat" when he's with DS. My response was to honestly say that if that works for them that's great, but don't be doing it for me - as far as I'm concerned the more positive role models DS has the better and it really is not up to me to declare someone suitable for DS in terms of my ex, that's her business.
I, sniff, have no new GF yet, so shoe hasn't been on other foot - if that ever were to happen, based on some other stuff - e.g. ex wanted to see my new flat before I moved in so she "could visualise where DS is" - could be interesting.
So I'd say this to OP. If you want your new GF to meet your daughter because their both important parts of your life then go for it. By definition in posting you're thinking about it carefully and lots of posts have given lots of different kinds of advice.
I'd say 4 things:
- Your DD is young and as has already been pointed out, won't grasp fully what GF actually is and certainly won't have a thought process where they decide you're trying to replace Mummy for her. You can make sure of that by managing a little how you and GF act around DD when your together, because if GF was just a friend suspect you wouldn't think twice about her co-inciding with your time with DD. So maybe go down that road while your relationship with GF develops one way or another.
- I think involving your ex with the decision and letting her know how you're going about it might alleviate any bad feeling a little. Many I'm sure will disagree with that, but my experience is that bad feeling normally stems more from lack of communication than over communication. However if you do I'd advise being assertive over some aspects (e.g. GF and DD ARE going to be spending time with me together because they're both very important to me) and where possible listening and acting on her concerns / needs (e.g. within that context do you have any advice or feelings about the best way to go about introducing them, etc). If she's angry and just dismisses it as a bad thing then so be it - at least you will have tried.
- Every separated / divorced parent walks a tightrope to a certain extent when it comes to new partners. Some would say new partners should only be introduced when you're very sure this is going to be a long term relationship and you've been together for ages and ages - but by definition that's a bit non sensical because my best guess is not many people who choose to have children together are thinking "well this might end, but lets have children anyway" - yet the fact that they separated suggests it did end and there's a risk with all "partner" relationships that they could end. Of course I'm not suggesting a revolving door of new partners is a good thing but I think if you've been seeing someone and it feels like it's going somewhere and it's managed gently and sensitively introducing a new partner to a child can be worthwhile. The flip side of waiting for ages is that it can put pressure on the new partner when they do meet or make new partners feel they're peripheral to your life because there's this massive part of your life they're witheld from.
- Which leads me on to my final point. There isn't much clue in your post as to whether your new GF wants to meet your DD? She might not want to? That would probably give you quite a clear steer on the future dynamic of the relationship for you?
Oh and all this stuff about age. Yep, it's quite a big age gap but there are no rules here. Increasingly age gaps seem to be less of a problem as society evolves. Age (beyond 18) as Ahliya once said, ain't nothing but a number.