rhapsodyinblues I can completely see why you are worried.
You sound like a lovely mum. You say I know it is not really my business Of course it is your business, she is your child.
It doesn't mean you get to tell her what to do, but it is your business.
I think it all sounds pretty worrying to me. It sounds like he is controlling, how can a woman possibly know if she wants to keep a baby before she is pregnant. I find the idea of using a unreliable method of contraceptive with a man you are not fully comfortable with (she must not be completely comfortable after family rows/you not going in on the house with him/open relationship etc - committed - not - my guess?
To me (IMHO) to plan how you will get rid of the baby if you do get pregnant, that all sounds very sad. No offence to anyone who has had an abortion or is planning one but many women do find it a terribly difficult decision and to be pushed into it 'effectively' before it happens! That is shocking to me and unless it is 100% consensual it sounds controlling.
I have had a lot of fertility issues and I feel that biological desires to have a baby can be pretty strong, your dd may feel differently if she gets pregnant, how will she or he cope, she would in some way be tied to him if she had a baby and chose to keep it.
I could have read it wrongly but it does sound controlling and like she may have been pushed into it. Plus if they have a genuinely open relationship and she has sex with an unreliable birth control method with another partner then she may well not know whose baby it is anyway, so it may well not be down to the boyfriend to say what he thinks about it at all!
Anyway, sadly, you won't be able to tell her what to do, and she is a young woman so she will make her decisions. Maybe she will decide on a career that takes her away from him, to a new city, maybe you will get to invest your money in a bachelorette pad for her elsewhere. in your shoes that would be what I would be hoping for!
My worries aside from the possibility she will have an abortion or a a pregnancy that does does not want AND that she may have a so called 'open relationship', which she may not want, (which frankly I feel is pretty euw - I mean I think young people normally want to feel their partner only has eyes for them, or am I terribly old fashioned (and happy to be!).
So aside form all that crap my worries would be:
She is in a relationship that has not been going for even two years, she is very young, they are not married, maybe only living together because his parents could afford to buy him a place and in your words 'as their relationship was going through a rocky patch' - I don't feel that is necessarily 'stable', to me and in her shoes I would want to keep my options open and not run the risk of getting pregnant or being pushed into an abortion (if that would be the case).
She is effectively putting her career on hold for a year for him, until he graduates, not sure if he would do the same for her (would he?)
Re BF said I'd got him all wrong and DD is very much in love and is happy that all is well. what does your dd say, in private?
Re living in the house no mortgage, so she will maybe not pay any mortgage or rent, she will pay for food and stuff, and when/if the relationship breaks up he will have a house! While if she bought a home with another friend/a different man/you guys she would pay a mortgage and food but end up with the asset of a home. He has effectively cut her options down while looking like he is generous!
And finally, to me, the most telling comment is "She comes home a lot and we are close." I wonder if she is so in love with him why she comes home so much?
In your shoes I would make it clear if she is not happy she can come home. No ifs or buts, no expectations on your part, no 'I told you do', just what is best for her. She is your priority, not this man who wants an open relationship with a woman who is very much in love with him (off to be sick in a bucket).
It's late so am being rather judgemental, I am sure he is a lovely lad!