Experiencing a pregnant wife by another man

As I have described in an earlier post, my wife and her lover (her ex) have conceived a child together. Much planning went into this decision and the act itself. I witnessed their lovemaking, for that is what it was no matter how much I try to deny it. This fucking was so much more then usual as there was a goal in mind. And he succeeded in seeding my wife. I have described the events leading up to that moment and my emotional journey.

My wife is now almost 5 months pregnant, due in May. Her pregnant belly has been showing for a couple of months now, a constant reminder of that act. I am excited and nervous about it, kind of sad and sometimes upset by it. But I was a willing participant, doing my part. I guess being a good cuckold for my wife and her lover. I have been asked, maybe demanded, to refrain from any kind of sex with my wife while his baby is growing inside of her.

Of course, they fuck, I often watch. My sexual relief is masturbation, mosting in private before, but now I masturbate and cum while they fuck. Supposedly once she delivers and is cleared for intercourse and is up for it, I can resume intercourse with my wife. I am infertile, as I had a vasectomy as part of this journey, so no chance of me knocking up my wife. That is what I wanted.
He is supposed to get a vasectomy at some point so my wife can stay off the pill. I thought it would have happend by now, but nothing seems to indicate it will be anytime soon.

Even though it is not my baby, seeing my wife naked, pregnant belly, breasts getting bigger, it so turns me on. I often wonder is it the fact that she is pregnant, the beauty of a naked pregnant woman, or the fact that it is his growing inside of her.

The plan is I will be named the father, raise him (yes it is a boy) as my own. I worry that this plan may change once the baby is born. He has been actively involved in the pregnancy, coming with us to doctor appointments, seeing the sonogram, hearing the heartbeat. My wife told the obgyn the situation, and it is a little awkward when the three of us show up for appointments. My wife did not tell her doctor that her ex fucked her, just that he was a sperm donor, as I was infertile and oh how much my wife and I wanted a baby and he was willing to help us out. I wonder if she buys it as I feel she looks at me as a cuckold. She would be right of course, for I am a cuckold.