Wow, what an uncomfortable situation for you. I agree that you should help her as a couple if you chose- taking care of kids, maybe even helping her run errands, etc.. And that is very kind and generous. 

DH shouldn’t be her main source of emotional support through this- that is disrespectful to you and your marriage. What would he think if one of your ex boyfriends was ill and you were doing the same? 

The kids is where it stops for me. If one parent is having a more difficult time in life because of any reason I think the other parent(s) should step it up with the kids- but that is as far as it should go. Just because you had a kid with someone doesn’t make you indebted for life to this person. When you think about it.... it would not be acceptable if they had been married for 20 years and had no kids- people would look at that as almost adulterous behaviour but because they have a kid it is all ok (even if they were only together a year or 2).

it just puts you in a horrible spot, either you are forced to tolerate it or you are being viewed as heartless or irrational. 

Let me say for the record... I would not expect nor want my exH to be so involved if I was in that situation (even if I wasn’t married to my DH now)— all I would expect is for him to help more with our DD. 

I guess I'd have to ask what happens after chemo., remission and so on and those appts. are no longer needed; or, what happens if it comes back?  I don't take responding to this lightly, as at one time I worked on breast cancer guidelines and my own mother suffered with breast cancer (Stage III) at an early age.  Thank goodness she survived and is now in her 80s.

This is part of what makes step-parenting so very difficult.  Much like your scenario, imagine if you were on a sinking boat and your DH could either save you/ his wife, or his ex-/ the mother of his children, but he could not save both.  (Let's say you and your DH had no children of your own.)  Who should or would he save?  Even tho. this is your husband, your partner for life, the one you exchanged vows with, I can assure you, there are many people who would say he should save his ex-, the mother of his children, because his children need their mother.  You, Pfft!  And, that is what some would say.

The answer to that question is not so easy as some like to think.  Many people out there just think about mom and dad and the kids and what they are going through.  A lot of people do not realize that SM (or step-dad) gets dragged into the middle of everything and anything the initial family is going through.  Thus, the initial family, usually with a little bit of work or outreach, can get the support they need.  SM or step-dad, well. . .  as usual, they are supposed to suck it up and take it, even though they may be suffering just as much, but in a different sort of way.  And, THAT is what very few realize or want to realize  Most are not lining up to support us; most are lining up to tell us to suck it up.

Thus, as a SM, you need to try to find your own resources, such as an empathetic counselor; or, even coming here to vent can help or at least help you to realize that, no, it is not you or just you.  I'm sure right now you are feeling like you are a stranger in your own marriage, and you are certainly not alone in that feeling.  I'd recommend trying to look at the situation as objectively as possible, because I strongly believe that a SM's instincts on what is right or wrong in her marriage are usually spot on.  Does he really need to call her every day?  Does he really need to take her to all of these appointments?  I do get him taking the kids to see her, tho.  Does it seem excessive to YOU.

As a married couple, you are supposed to be able to approach your spouse with any issue or concern, and sometimes I find alarming how often spouses, our DH's blow these things off by claiming their wife, their joined-at-the-hip partner is out of it or being heartless or cruel.  This is just me, but I'd start out by seeing a counselor myself, and then, because maybe this is just too new for everyone right now, I'd start to focus on and even try to direct some of the discussions with your DH on what is the future going to look like for you and him once these treatments have ended?  Because to me, that is the biggest question.  I mean, is he planning on being by her side for life now, because you never know what is going to happen one day to the next?  Or, is he doing this first and foremost to make things better for his children?

Intent.  That is what you need to try to breakdown and analyze.  You stated he was spending time with you and your child too.  Maybe his main intent is to make things better for his kids as much as possible.  And, even if that it true, what does that mean for you?  These are all complicated questions (with complicated answers) and that is why professional help would be best.  On the other hand, if you get the strong feeling there is a level of inappropriateness to all of this, in the sense that it is too over the top with him focusing on BM (who is another woman, regardless of whether she is the mother of his children or not), and you feel you are being cheated somehow, then you need to ask yourself where do I go from here.

A long post, but you have a very complicated situation here.  No, you are not being heartless.  And, avoid those family members and buddies who have never been SMs or even close.  They'll rarely get it.  But, do see an empathetic counselor (and don't hesitate to change counselors, if you have to) and try to get at the heart of the issue, and one who can recommend ideas, or even bringing your DH into counseling too.  Whatever you do, though, don't forget yourself!

I was thinking about it more... and it seems almost like divorce guilt. Like living the “in sickness and in health” thing. 

I would be livid.  I wouldn’t express that to other people, but DH certainly would be getting an ear full from me. 

If he was single ok.... but I think he is taking it way too far. 

Like would he maybe like for you to step out of the picture so he can devote his time to her care? 

I really feel for you.

Here is what someone said on the subject on another site, which I thought sounded reasonable: "helping out is cool...'taking care of' is NOT.  ..andif she or he is doing it to 'hang onto' the other any way they can, then no." 

So, do you feel his intent is to help out or to take care of?  Helping out = maybe OK.  On the other hand, taking care of means he is assuming responsibility for.  Very few women want to be married to a man taking responsibility for another similarly-aged woman, much less an ex-. In the US, a man (or woman) only has one spouse--at a time.  BM may be the mother of his children, but, again, this doesn't give someone a free pass to do whatever they want or feel like doing.  They divorced, and he is now married to you. 

You are or are supposed to be his #1 spouse.  The term 2nd wife doesn't really exist anywhere in the U.S. other than in print (or a couple of polygamous sects that are left), but if he now has responsibility for two women, then I can very much see where you feel like a 2nd wife, literally.  It's okay for him to help her out, like take the kids to visit her, but things like calling her every day or taking her to appts. someone else could take her to. . . seems to go beyond helping out.  And, if his ex- passes, and you are suddenly expected to somehow fill her shoes w/his children, he has already made it apparent to his 3 that you are his #2 wife, and thus, lesser of the 2, and why should his kids take you or the marriage between you and your husband seriously if he doesn't?  I'm not saying he is doing it on purpose, but if he is running around trying to make his ex- "comfortable" at your expense, this is part of what his children are seeing too.

While DH is no longer married to BM she did bear his children.  At some level DH probably feels some guilt and obligation.

If I were DH I would limit my personal interface with BM and increase interface with the Skids.  Fortunately I have not had to navigate the death of a parent or a spouse either X or otherwise.

Though BM is likely dying she is no longer DH's wife. You are.  He needs to be at your side and not hers.

IMHO of course.

I'm a cancer survivor myself (hodgkins stage III) and have several coworkers have survived breast cancer one even went through chemo while pregnant. I think even stage  III has a pretty high survival rate with the current treatments. I will say that going through treatment is hard and I wouldn't wish it on anyone but if she has so much support from family it seems weird that she's really on her ex so much. I worked while going through chemo and drive myself to most appointments.

I think it's fair to help with the kids but I think he's going further than he needs to to help her out.

The fact that she had his kids does not give carte blanche to be taken care of like family. She needs to find someone else to emotionally support her, and your husband needs to make the distinction between what he is doing and what he THINKS he is doing.

If he wouldn't do it for any if his other past exes, he shouldn't do it for her. Babymom doesn't mean responsibility.

Here is the link to the earlier post.  Just placing it here so others can see and learn: https://www.steptalk.org/forum/general-discussion/its-official-dh-leavin...

No OP, you were not heartless, but your DH is and was.  Given that DH has fallen in love with his "suffering" wife all over again while apparently falling out of love with you, and given that there is a high probability she will survive, I just wonder what DH will feel once she (more than likely) goes back to her ol' self again, the one he divorced?  Maybe they have both learned lessons now, I don't know, but, regardless, I think the one who learned the best lesson was you!  You learned to trust your gut, and you learned that the reason DH and BM were so kissy-face wasn't due to your lack of understanding or empathy, but rather due to them letting their hormones get the best of them.  Now you know you are a good person and can raise a good daughter.  Time will tell what happens with DH and his ex-, but I have a funny feeling in some odd way they deserve each other.  You, on the other hand, go on with your daughter and lead a fulfilling life for yourself and her.