Italiangreyhound - I too am in a marriage where we are of two different Christian denomonations, both very active in our own churches when we met, and as I was writing a degree thesis at the time on inter-church marriage, I had looked at the theological issues carefully prior to marriage. It meant that my husband and I went on two different marriage preparation courses, one specifically on inter-faith marriage. This meant that we were in the fortunate position of being able to have an open discussion about infant baptism in the different denominations prior to having children.
Obviously the OP and her dh did not have this discussion prior to children, and they both panicked !!!!! I think that your blaming the OP's husband is wrong, they were both at fault. But the OP went a step further and organised a secret baptism for their child.
You ask how did he not create the issue, it was both of them that created the issue, as both of them are at fault for not having communication prior to the child arriving. Whether his manner was threatening, I would question, as he offered the solution to leave it to the child to decide, this in the situation of inter-church marriage, is a valid solution, as are several other options. The having the child baptised in secret is not a real solution, it was a get out of having to come to a compromise via discussion.
In my situation, my husband compromised with our first child, and we did agree to wait and let our child decide, but family pressure was continually put on him about getting our child baptised, that when we had our second child, my husband and I talked about it further, and in order to relieve some of the pressure his family were putting on him, he agreed to have our second child baptised in the church I am in, the church we were married in.
The OP was not forced by her husband to baptise their child in secret, it was a lack of communication and she decided to act unilaterally outside of their marriage agreement if you like. He may or may not have threatened at the time to instigate divorce if she baptised the child in her church. If family pressure was anything like the situation my husband had to endure, I can understand why the husband may have talked about it in this way, that it could put the marriage under so much pressure that it could break. He was wrong to do that sort of threat after his wife had just had a baby, and will need to apologise for this, but they were both wrong to have left it til crunch point of the baby being born before discussing it.
I think that you have a very dim view of church counseling if you think that going to a counseling of a different denomination is going to brow-beat you into a particular way. I have found that it is helpful to go to the church that is not your own, in order to understand why my husband has a particular view on issues, and sometimes help my husband see that marriage vows are important.
The catholic church says that in an inter-faith marriage, decisions regarding children have to be made "within the sanctity of marriage" so that the catholic church does not make baptising of children above the marriage vows in importance. Baptising of the children is not supposed to end up with breaking the marriage. Hence the availability in both churches to allow for children to remain unbaptised as infants, although not an ideal position, but putting the marriage at risk is considered a worse situation. This came about in the Catholic church at Vatican 2 due to the problems that at the time, there was no choice for Catholics, they had to get their children baptised into the Catholic church as infants. It lead to huge issues in marriages.
"I feel very sorry for the OP because if she had felt able to, I hope, she could have found a compromise with her dh." - This is the issue, she was not able to discuss it prior to having the baby and then not able to reach a compromise after having the baby, the OP chose to do her own thing rather than discussing it and finding a compromise. There was not theological reason for her to do what she did, when she did it, she did not apparently seek advice from her spiritual leaders at the time regarding it, but went ahead without her husbands consent, and is contemplating doing the same again. This is very much a breach of trust. If she had sort help from her church and arranged marriage counseling from her own church leaders at the time, they may or may not have persuaded her and her husband to get baptism done at that time. But the OP does not say it was on advice of her church, it was just because she was unable to compromise at that time, and she felt that the only way to get her child baptised was to do it in secret.
The marriage still needs to be worked on. Hence why I am asking her to think about what she has done, so she can have honest answers to give to her husband when he asks "why"! Can she honestly say that the only reason she got her child baptised in secret was because he threatened divorce! No it was also because she was unwilling to compromise her beliefs. The church would have told her to put her marriage first, try to sort out the issues, but she did not do this as she just wanted to get the child baptised regardless. That is how I read it when she says "Now I would like nothing more than to baptise DC2 at my church but it would mean the same happening again as DH has reiterated he would not consent to having his children baptized." In other words he has again said he is not happy having their child baptised in the Orthodox church and would prefer to wait to let the child decide later in life. Yet the OP (not under immediate threat of divorce this time as far as I can see) is thinking about getting their second child secretly baptised, rather than seeking marriage counseling from anywhere, to deal with this very difficult issue. At the very least, both of them need to go to both churches and get advice about their marriage as well as the issue of baptism.
Her husband is not in the right, neither is she, they both need to deal with it, preferably together.