This is a serious question. I'm asking it here because I want a diversity of opinions on the issue, I don't want any censored opinions, and I don't want the truth to be obscured or avoided because it could make me uncomfortable.

My situation: I'm a 24 y.o. straight woman. I'd like to be in a monogamous LTR and, ideally, to get married to a man and to have a close and emotionally intimate relationship. While I want to have my own source of income (especially if I'm not married - if I were married I'd be open to not working if my partner and I desired that), a career isn't the only priority in my life and I don't plan on pursuing one at the expense of connecting with my partner, taking care of myself/my health, prioritizing friends and family, and exploring interests unrelated to my job. I'm on the fence about having kids, and the conditions under which I'd do so are unusual. While I'm open to having kids through adoption or through becoming a stepmother, I do not want to become pregnant and bear any children myself. Alternatively, I may end up satisfied living a childfree lifestyle with (hopefully) a long-term partner/husband who is also childfree.

My question: Is this realistic? In your opinions, is it realistic to expect a man to still be invested in me and interested in me as a partner when I'm in my late 30s, 40s, 50s, and beyond when I have not borne any offspring that shares our DNA? Or is the harsh truth that he, having lived longer and attained more resources, would fantasize about leaving me for a younger woman and perhaps even go ahead and do so because he can? Basically, do I have significant value to a long-term male partner beyond my attractiveness/youth and my childbearing ability (the latter of which I intend not to use)? Would my relationship with him have a shelf life that ends when I'm no longer attractive? Would I be without value to him once I'm old if I haven't borne our genetic offspring?