Hi Maybell, that's a tough one and I'm sorry you feel that way. Your feelings are perfectly valid and I can see that must be difficult. There is a balance between being a decent ex and holding a candle for your previous relationship. I can't recall if they have kids? If they do, that brings more obligation and responsibility. Though of course that needn't extend to significant maintenance jobs.
When I was with ex H, we had quite a lot to do with his former wife. I met her a year or so after I started dating him, and we were on good terms. Actually, when I came into the mix, things seemed to ease somewhat with them. Maybe some more closure on their D? IDK. We got involved in some small renovation projects in her house, but it was nice and we helped her with those together. Also had some dinners together, and she and I have remained on friendly terms since XH and I split up.
If he doesn't have kids with her - and does big jobs like this for her - I would be particularly concerned, as that just seems like not letting go of 'what was.' If they do have kids, it is more understandable - but perhaps a little OTT? What were the circumstances of their R ending? Her choice or his? And how long ago?
I guess he will do what he will do, and if it is a boundary issue for you, it is an elephant in the room unless you raise it. The pattern would be that you withold from him, and some intimacy is lost...etc...
Perhaps you might suggest meeting her? In any case, if you are invested in this R and you are concerned about his investment, I would certainly address it...
Hope this helps a little :)xx
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus