Before he married our daughter in law, our son was always friendly to us, and we thought that it would continue in this way. We bought an apartment for him and his now wife to live in before they were married and then they were listed in the telephone book just like us, and would answer their telephone if we or anyone else called. Both he and his now wife (DIL) could not get a loan to buy their first home so asked if we would go as guarantors for their home, which we did. They were married at the end of last year, and because we did not want to interefere too much in their wedding day plans we offered to give them the money for any wedding cake of their choice, as well as to pay for their airline tickets around the world as they were going on their honeymoon around the world.
We thought that everything was OK, but now they have been married for nine months both our son and DIL are becoming more and more distant. I bought her a small box of chocolates for Mother's Day last year, but was told this year by our son that she was totally offended by this and that I was not to do this again, which I did not. Before they were married they had a short holiday in Bangkok and there was a military coup there at the time, so we called to see if our son and DIL were OK. This call is always remembered and spoken about by DIL as being silly and uneccessary, but we were worried about them, and would worry if any of our friends or relatives would be in a place where there was a military coup.
We think that it is OK to talk to our son once a week on the telephone but every time we call, the message bank comes up and they never call back. So we ask to meet him for coffee or lunch sometimes near his work, but DIL always comes as well, which is OK, but then she controls all the conversation, and even puts our son down so that we cannot talk to him.
It is very sad for us, as our other two children and grandson see us all the time, whenever any of us wants to, except now for our elder son, who seems embarrassed or scared to see us once a week or fortnight.
A few years ago, before they were married, our son broke off his engagement with our now DIL, and she would call me day and night and refused to move out of the apartment that we had bought and that she shared with our son. I was very kind to her, and encouraged my son to go back to her, but now I am sorry that I did, as she does not want any relationship with us at all now. When our son bought his wedding ring he called to tell us, and because we thought we were being nice, we asked to see it, but she responded straight away with "nope".
We just want a warm and kind relationship with our DIL and son, but it seems further and further away.

Any suggestions