i had a similar situation as well, with my ex taking off for a 6 weeks trip and doing exactly what your OH is now. the trip was planned beforehand but he didn't cancel it although it has been a week only since we lost our baby.
this is a hard core denial, as well the phrase: "we should try again" is really just a men's desperate attempt to "fix" things that can't be fixed. it is like: "ok, she needs this and this and this from home. ok, got that. now, we lost this baby - shit and devastation - so let's make a new one to take all that away."
but it doesn't work this way, it doesn't work either for them. it just takes them a while to click. it is not their body so they can go into this phase much easier than a woman can. they can act all happy and excited and whatnot, but there's a deep deep restlessness below. it just takes a while for them to surrender to it. especially these kind of practical problem solvers who can take anything but feeling helpless. i don't know if he has ever lost anyone in his family, but i tell you - he'll come around, it just takes a while to hit him. maybe not even immediately when he's back from his trip.
this was the case with my ex - came back and i had to listen about his travels and whenever i mentioned i needed us to talk about our baby he would just say he ain't ready. this went on for months and it was one of the hardest things i had to deal with in my life. he eventually broke down almost 10 months after the loss and then came all the words and things i really really really needed and longed to hear.
my advice is yes, give him some time to get his head around, but also if you really need to talk, tell him. tell him that despite being sad yourself, you want to know what his true feelings are, that you know he's feeling helpless and incapable of helping you and solving the situation, but that making a new baby doesn't replace the one you've lost, like losing a sibling isn't easier because you already have another...
tell him, without attacking him, that you do know that he cared about your lost baby but that you need him to show that to you more openly, as this denial he is in is really hurting you and making you feel alone.
that the best way to help you is to expose himself to the reality of the loss you guys have suffered as a couple, or at least that you have suffered as a woman - because you have also lost something that was a part of your body as well.
maybe even look for a grief councilor or a couple therapist. this i say as the lack of communication and the running away from facing things on his side for all that time has ruined the relationship we were in and it ended for good. i now have another OH which i wouldn't trade for the world, yet if that previous relationship would have ended differently, still with a break up but in a less devastating way, it would have made my life way way simpler.
miscarriage really really affects relationships, even the strongest ones, but it doesn't mean the end due to the hardships. it may even bring you closer after a while.
i am sending you a huge huge huge hug.
